Synchronize with the latest Klipper code. This pulls in the latest
lib/ files (needed to use the pico-sdk v2.0.0 version). It updates to
latest can2040 code (needed for pico-sdk v2.0.0 support). It
implements USB double buffering (as is now done in Klipper). It adds
in support for additional UART pins (as is now done in Klipper). It
adds support for rp2350 chips.
This replaces the execute in ram code previously implemented in
Katapult with the execute in ram code that is now standard in Klipper.
The CONFIG_RP2040_ADD_BOOT_SIGNATURE kconfig symbol was removed and
the build now always produces a katapult.withclear.uf2 file.
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
