Prefer using 'uint8_t' buffers as it is too easy to run into C sign
extension problems with 'char' buffers. Prefer using 'uint_fast8_t'
for buffer lengths as gcc does a better job compiling them on 32bit
mcus.
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
Instead of creating a misc.h file in each board directory, create a
generic board directory and declare misc.h there.
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>