Using pico-sdk develop branch, add in support for CYW43-based
WiFi/BT/BLE boards on the RP2350 such as the
SparkFun Thing Plus RP2350 or the Pimoroni Pico Plus 2W.
Fixes#2608
Rolls in dynamic SPI divider #2600
* Support LED digitalWrite on RP2350+CYW
Also move "special GPIO" to 64 since the Pimoroni Pico 2W uses the
RP2350B with 48 GPIOs.
* Enable CYW43_PIN_WL_DYNAMIC in IDE and P.IO
Allows calling `cyw43_set_pins_wl(cyw43_pin_array);` to redefine the
CYW43 hookup in the variant initialization.
* Add SparkFun Thing Plus RP2350
* Add Thing Plus RP2350 PSRAM definition
* Remove radio from Thing Plus RP2350
Will need to add back once full radio support is added, see #2605
