targets/litex_acorn_baseboard: Integrate WS2812/NeoPixel.
targets/litex_acorn_baseboard: Integrate WS2812/NeoPixel.

Tested with:
./litex_acorn_baseboard.py --cpu-type=None --uart-name=uartbone --with-ws2812 --build --csr-csv=csr.csv --load
litex_server --uart --uart-port=/dev/ttyUSBX
And test script: https://gist.github.com/enjoy-digital/c32c679a9ee4429d7f38a5ca5016a45a

litex-hub/litex-boards