Remove two SPARKFUN_SAMD51_THINGS_PLUS pin definitions. There were
definitions of TXD and RXD, but these pins do not exist on the board. They
were only shown in the schematics.
Also remove any reference to LED_. This is just a text change, no
functional change.
Changes are:
- Remove the LED_Pxxx definitions from pins.csv, now that the LED class is
gone.
- Remove the '-' lines.
- Add default lines for USB and SWCLK, SWDIO.
This will be used by https://micropython.org/download/ to generate the
full listing of boards and firmware files.
Optionally supports a board.md for additional customisation of the
download page, as well as deploy.md for flashing instructions.
Signed-off-by: Jim Mussared <jim.mussared@gmail.com>