[PATCH] driver/base/memory.c: handle errors properly

Do proper error-checking and propagation in drivers/base/memory.c, hence fix
__must_check warnings.

Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>