The functions `hw_write_masked` and `hw_xor_bits` (as defined in
pico-sdk) were defined in NuttX twice.
Additionally these definitions were in conflict (one lacked the
`volatile` modifier).
Now these functions and their dependencies are defined in a new header
file.
Its name is based on the filename of the original definition in
pico-sdk:
src/rp2_common/hardware_base/include/hardware/address_mapped.h
This change should fix the potential issue of GPIO operations failing
due to compiler optimizations caused by the absence of `volatile`.
Signed-off-by: Lars Kruse <devel@sumpfralle.de>
b3dd8b2796