Add flush size on TinyUSB example

[21km43]

Running the TinyUSB test on the CH32V203C6T6 may result in insufficient Flush. I have changed the board used for testing to CH32V203C8T6 which has 64KB flash size.

Checking size .pio/build/genericCH32V203C6T6_tinyusb_usbd/firmware.elf
Advanced Memory Usage is available via "PlatformIO Home > Project Inspect"
RAM:   [=====     ]  47.1% (used 4824 bytes from 10240 bytes)
Error: The program size (34644 bytes) is greater than maximum allowed (32768 bytes)
Flash: [==========]  105.7% (used 34644 bytes from 32768 bytes)
*** [checkprogsize] Explicit exit, status 1

========================== [FAILED] Took 6.29 seconds ==========================