Add board port for Pimoroni Pico Plus 2 W

[eightycc]

CP supports the Pimoroni Pico Plus 2 board but lacks support for the new W variant. The Pico Plus 2 W includes a Raspberry Pi RM2 adding WiFi and Bluetooth capabilities that should be compatible with the Infineon CYW43439 on the Raspberry Pi Pico W boards.

I'll claim this issue and will submit a pull request as soon as my test board arrives.

[anecdata]

Related: #9777

[bablokb]

I already have (two) of these boards. If I can help in any way, just let me know.

[eightycc]

Thanks to @anecdata for pointing to micropython#16057 where a similar Micropython port is underway. Making a first pass through the PR and the changes it makes I can see that RP2350/RM2 changes depend on SDK changes to its develop branch. Likewise, cyw43-driver module will also need an update.

The cyw43-driver change is to TSSI calibration, so CP doesn't necessarily need it.

The PR issue that affects CP is achieving proper adjustment of the PIO clock speed. The CYW43439 communicates with its host using a SPI variant named gSPI. The cyw43-driver uses a PIO to emulate gSPI.

It's probably wise to wait for this PR to shake out.