Add new board Silicognition RP2040-Shim, RP2040 with 4 MB of flash
and W5500 drivers included and configured by default for use with
the Silicognition PoE-FeatherWing.
Co-authored-by: Matt Trentini <matt.trentini@gmail.com>
Signed-off-by: Patrick Van Oosterwijck <patrick@silicognition.com>