Make it compile with CONFIG_PM=n

Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Jeff Garzik <jgarzik@pobox.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>