Replaces the previous all-zeroes "TODO" serial number.
Requires refactoring the low-level unique_id routine out from modmachine.c.
This work was funded through GitHub Sponsors.
Signed-off-by: Angus Gratton <angus@redyak.com.au>
Functionality and code size don't really change, but removes port-specific
code in favour of shared code.
(The MSC implemented in shared/tinyusb depends on some functions in the
pico-sdk, so this change doesn't make this available for samd.)
This work was funded through GitHub Sponsors.
Signed-off-by: Angus Gratton <angus@redyak.com.au>