Clean up mcuboot child image config

- Remove unused UART options
- Changed RTT mode to trim no block
- Set log level to warn
- Turned off debugging
- Removed mcumgr echo for testing

app/child_image/mcuboot.conf

@@ -1,9 +1,6 @@
 # Core should be on a clean state when TF-M starts
 CONFIG_MCUBOOT_CLEANUP_ARM_CORE=y
 
-# Enable echo command
-CONFIG_BOOT_MGMT_ECHO=y
-
 # Increase MCUboot image sectors and set static partition size
 CONFIG_BOOT_MAX_IMG_SECTORS=256
 CONFIG_PM_PARTITION_SIZE_MCUBOOT=0x20000
@@ -32,27 +29,22 @@ CONFIG_SPI_NOR_FLASH_LAYOUT_PAGE_SIZE=4096
 CONFIG_PM_EXTERNAL_FLASH_MCUBOOT_SECONDARY=y
 CONFIG_PM_OVERRIDE_EXTERNAL_DRIVER_CHECK=y
 
-# Logging RTT
+# Console
 CONFIG_CONSOLE=y
-CONFIG_UART_CONSOLE=n
+
+# Logging
 CONFIG_LOG=y
-CONFIG_LOG_DEFAULT_LEVEL=3
 CONFIG_LOG_MODE_MINIMAL=n
-CONFIG_LOG_MODE_IMMEDIATE=y
-CONFIG_RTT_CONSOLE=y
+CONFIG_LOG_DEFAULT_LEVEL=2
+
+# RTT
+# We use serial for MCUmgr so no UART
 CONFIG_USE_SEGGER_RTT=y
+CONFIG_UART_CONSOLE=n
+CONFIG_RTT_CONSOLE=y
 CONFIG_LOG_BACKEND_RTT=y
 CONFIG_LOG_BACKEND_UART=n
-CONFIG_DEBUG=y
-CONFIG_LOG_BACKEND_RTT_MODE_DROP=y
-
-# # Logging UART
-# CONFIG_CONSOLE=y
-# CONFIG_UART_CONSOLE=y
-# CONFIG_LOG=y
-# CONFIG_LOG_DEFAULT_LEVEL=3
-# CONFIG_LOG_MODE_MINIMAL=n
-# CONFIG_LOG_MODE_IMMEDIATE=y
-# CONFIG_LOG_BACKEND_UART=y
-# CONFIG_DEBUG=y
-# CONFIG_LOG_MODE_OVERFLOW=y
+CONFIG_SEGGER_RTT_MODE_NO_BLOCK_TRIM=y
+
+# Debugging
+CONFIG_DEBUG=n