Using 0x%d is wrong.  Emit a message when it happens.

Miscellanea:

Improve the %Lu warning to match formats like %16Lu.
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>