blackfin: Cleanup linker script using new linker script macros.

Signed-off-by: Tim Abbott <tabbott@ksplice.com>
Cc: Bryan Wu <cooloney@kernel.org>
Cc: uclinux-dist-devel@blackfin.uclinux.org
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Mike Frysinger <vapier.adi@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>