Blackfin: bf51x/bf52x: drop redundant "base" def/cdef header

The defBF512.h header exists only to include defBF51x_base.h, and it is
the only place where defBF51x_base.h is included.  So move the contents
of the defBF51x_base.h header into the defBF512.h header.

Same situation for the other def/cdef pairs.
Signed-off-by: Mike Frysinger <vapier@gentoo.org>