The pico-sdk codebase currently fails to compile with strict warning flags. When building with -Werror -Wall…

The pico-sdk codebase currently fails to compile with strict warning flags. When building with -Werror -Wall…: a task in LegoFlow-SWE (Harbor dataset). The SDK should be able to compile cleanly with these flags so that projects using the SDK can enable strict warnings without tripping on SDK code.