make suspend quieter

Fix a goof in Linus' recent PM API updates:  don't emit any messages in the
typical NOP "already suspended it" late suspend case.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>