Fixup PlatformIO CI

* Output UART PRINTF on a default Port A9

v30x, v20x, v10x support 

Improve use of Link-E, making it automatically exit IAP and ARM modes, as well as try very aggressively to reset the processor if it can't attach.

Simplify UART_BRR calculation

Add header definition for SetupUART Closes #250

* Add mco example

 * Unify linker scripts
 * Switch Init section to be "used"
 * Switch ch32v203 to be rv32imac, not imafc

Merge branch 'other-chip-support' of https://github.com/AlexanderMandera/ch32v003fun into AlexanderMandera-other-chip-support

fix compilation for arch linux

on arch linux, the risc compiler name is different.
Add some logic to pick correct risc compiler on arch linux

Signed-off-by: Amitesh Singh <singh.amitesh@gmail.com>

Fix comment

Add `-fdata-sections` to compile flags