Blackfin: bf561: fix mem_map.h SMP overrides

The BF561 mem_map.h header has the __ASSEMBLY__/CONFIG_SMP checks out
of order which leads to build errors for assembly code that happens to
include this file.

Signed-off-by: Graf Yang <graf.yang@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>