Since the introduction of the rp2350, the pico-sdk project has been
re-arranged and elf2uf2 has been merged in to a new 'picotool' binary
which is supplied and installed separately.
Summary:
- In the previous implementation, the build system stops if
PICO_SDK_PATH is not set.
- However, this behavior is not good for CI. Because the path
is only used to generate a flash image.
- This commit fixes this issue
Impact:
- rp2040 only
Testing:
- Tested with and without PICO_SDK_PATH