Blackfin arch: move board specific setup out of common init code and into the...

Blackfin arch: move board specific setup out of common init code and into the board specific init code

Signed-off-by: Mike Frysinger <michael.frysinger@analog.com>
Signed-off-by: Bryan Wu <bryan.wu@analog.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>