Blackfin: use on-chip reset func with newer parts

Blackfin: use on-chip reset func with newer parts

Turns out the documentation is wrong and doing "RAISE 1" does not result
in a software reset, only a core reset.  So when the on-chip rom has a
functioning reset helper, use it.

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