ARM: clps711x: fix missing include file

linux/bug.h is needed due to an ARRAY_SIZE being used:

arch/arm/mach-clps711x/edb7211-mm.c: In function 'edb7211_map_io':
arch/arm/mach-clps711x/edb7211-mm.c:79:9: error: implicit declaration of function 'BUILD_BUG_ON_ZERO'

Signed-off-by: Olof Johansson <olof@lixom.net>