ARM: 7267/1: Remove BUILD_BUG_ON from asm/bug.h

BUILD_BUG_ON is defined in linux/kernel.h but that is not included by the
asm/bug.h header which uses it. This causes a build error:

...include/linux/mtd/map.h: In function 'inline_map_read':
...include/linux/mtd/map.h:408:3: error: implicit declaration of function
'BUILD_BUG_ON' [-Werror=implicit-function-declaration]

The check is not essential and is not present for other architectures, so
just remove it.

Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>