Merge #19923 #19927 #19933

19923: boards: add Silabs EFM32 Giant Gecko GG11 Starter Kit r=miri64 a=gschorcht

### Contribution description

The PR adds the support for the EFM32GG11B family and the Silabs EFM32 Giant Gecko GG11 Starter Kit board.

The Silabs EFM32 Giant Gecko GG11 has the following on-board features:

- EFM32GG11B MCU with 2 MB flash and 512 kB RAM
- J-Link USB debugger
- 176x176 RGB LCD (not supported)
- 2 user buttons, 2 user RGB LEDs and a touch slider
- Si7021 Relative Humidity and Temperature Sensor
- Si7210 Hall-Effect Sensor (not supported)
- USB OTG interface (Device mode supported)
- 32 MByte Quad-SPI Flash (not supported yet)
- SD card slot (not supported yet, follow-up PR based on PR #19760)
- RJ-45 Ethernet (not supported)
- Dual microphones (not supported)

### Testing procedure

Basic tests should work.

### Issues/PRs references

19927: sys/shell/ping: fix ping packet size overflow r=miri64 a=krzysztof-cabaj

### Contribution description

In #19829 `@mchesser` point out integer overflow in the ```ping``` command and API. This PR fix this issue in two ways:
1) Add protection in the API.
2) Add protection in the user command.

### Testing procedure

Without this PR passing negative number to the ```ping -s``` option cause segmentation fault, for example in the 
```example/gnrc_networking```:

```
> ping -s -7 ::1
ping -s -7 ::1
Segmentation fault
```

With this PR user shows appropriate warning test:

```
> ping -s -7 ::1
ping -s -7 ::1
ICMPv6 datagram size should be in range <0, 65527>.
> 
``` 

### Issues/PRs references

Issue #19829 

19933: examples/gcoap: add saml11-xpro to CI boards with insufficient memory r=miri64 a=krzysztof-cabaj

### Contribution description

Bors run for PR #19927 reveals that ```examples\gcoap``` do not fit in saml11-xpro board. 
I checked and this same linker error also appears on current master branch. 

This PR add sampl11-xpro board to the Makefile.ci BOARD_INSUFFICIENT_MEMORY list.

### Testing procedure

See logs from bors https://ci.riot-os.org/details/073c5dadc6ba4bc8a613edb78a1a4a2d

### Issues/PRs references

PR #19927 


Co-authored-by: Gunar Schorcht <[email protected]>
Co-authored-by: krzysztof-cabaj <[email protected]>

boards/slstk3701a/Kconfig

@@ -0,0 +1,32 @@
+# Copyright (c) 2020 HAW Hamburg
+#
+# This file is subject to the terms and conditions of the GNU Lesser
+# General Public License v2.1. See the file LICENSE in the top level
+# directory for more details.
+
+config BOARD
+    default "slstk3701a" if BOARD_SLSTK3701A
+
+config BOARD_SLSTK3701A
+    bool
+    default y
+    select BOARD_COMMON_SILABS
+    select CPU_MODEL_EFM32GG11B820F2048GL192
+    select HAS_PERIPH_ADC
+    select HAS_PERIPH_DAC
+    select HAS_PERIPH_I2C
+    select HAS_PERIPH_RTC
+    select HAS_PERIPH_RTT
+    select HAS_PERIPH_SPI
+    select HAS_PERIPH_TIMER
+    select HAS_PERIPH_UART
+    select HAS_PERIPH_UART_MODECFG
+    select HAS_PERIPH_USBDEV
+
+    select HAVE_SAUL_GPIO
+    select HAVE_SI7021
+
+    select MODULE_SILABS_AEM if TEST_KCONFIG
+    select MODULE_SILABS_BC if TEST_KCONFIG
+
+source "$(RIOTBOARD)/common/silabs/Kconfig"

boards/slstk3701a/Makefile

@@ -0,0 +1,5 @@
+MODULE = board
+
+DIRS = $(RIOTBOARD)/common/silabs
+
+include $(RIOTBASE)/Makefile.base

boards/slstk3701a/Makefile.dep

@@ -0,0 +1,13 @@
+ifneq (,$(filter saul_default,$(USEMODULE)))
+  USEMODULE += efm32_coretemp
+  USEMODULE += saul_gpio
+  USEMODULE += si7021
+endif
+
+# add board common drivers
+USEMODULE += boards_common_silabs
+USEMODULE += silabs_aem
+USEMODULE += silabs_bc
+
+# include board common dependencies
+include $(RIOTBOARD)/common/silabs/Makefile.dep

boards/slstk3701a/Makefile.features

@@ -0,0 +1,16 @@
+CPU = efm32
+CPU_FAM = efm32gg11b
+CPU_MODEL = efm32gg11b820f2048gl192
+
+# Put defined MCU peripherals here (in alphabetical order)
+FEATURES_PROVIDED += periph_adc
+FEATURES_PROVIDED += periph_dac
+FEATURES_PROVIDED += periph_i2c
+FEATURES_PROVIDED += periph_rtc
+FEATURES_PROVIDED += periph_rtt
+FEATURES_PROVIDED += periph_spi
+FEATURES_PROVIDED += periph_timer
+FEATURES_PROVIDED += periph_uart periph_uart_modecfg
+FEATURES_PROVIDED += periph_usbdev
+
+include $(RIOTBOARD)/common/silabs/Makefile.features

boards/slstk3701a/Makefile.include

@@ -0,0 +1,12 @@
+# set default port depending on operating system
+PORT_LINUX ?= /dev/ttyACM0
+PORT_DARWIN ?= $(firstword $(sort $(wildcard /dev/tty.usbmodem*)))
+
+# setup serial terminal
+include $(RIOTMAKE)/tools/serial.inc.mk
+
+# setup JLink for flashing
+JLINK_PRE_FLASH = r
+
+# include board common
+include $(RIOTBOARD)/common/silabs/Makefile.include

boards/slstk3701a/board.c

@@ -0,0 +1,31 @@
+/*
+ * Copyright (C) 2015-2020 Freie Universität Berlin
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @ingroup     boards_slstk3701a
+ * @{
+ *
+ * @file
+ * @brief       Board specific implementations SLSTK3701A board
+ *
+ * @author      Hauke Petersen <[email protected]>
+ * @author      Bas Stottelaar <[email protected]>
+ *
+ * @}
+ */
+
+#include "board.h"
+#include "board_common.h"
+
+void board_init(void)
+{
+#ifndef RIOTBOOT
+    /* perform common board initialization */
+    board_common_init();
+#endif
+}