doxygen really wants the @defgroup _and_ the @addtogroup to both have
the full name, matching identically, to avoid all warnings.
Standardize on the "CAPS_PERIPH peripheral API" style.
This shows what is _actually_ different for f7. A couple of option
bits, and a renaming of bit 7 of the status register, from Program
Sequence Error to Erase Sequence Error.
We keep the separate implementation of wait_for_last_operation, to meet
the "suggestions" of the reference manual to insert a DSB instruction.
Keeping the renamed bit/functions also requires us to keep separate
implementations of the flag clearing functions
