Blackfin: bf533: merge fio_flag back into normal mach headers

We don't want the BF533 to be different in terms of its MMR headers, so
merge the FIO_FLAG helpers back into the normal place.  To avoid circular
dependencies with headers, turn the inline C funcs into CPP defines.  Not
like there will be any code size differences.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>