Pin defines are:
- For Pico define board pins and the default LED pin (WL_GPIO25).
- For Pico-W define board pins, external pins and the default
LED pin (WL_GPIO0).
- For the Nano-RP2040, define board pins, external pins and
the default LED pin (GPIO25)
- For all other boards, the pins.csv defines the LED pin (if any)
for backwards compatibility with code that assumes there's always
an LED pin.
In most cases, it's calculated automatically from the board name, and so
doesn't need to be set at all.
Signed-off-by: Jim Mussared <jim.mussared@gmail.com>