[PATCH] Driver core: PM_DEBUG device suspend() messages become informative

This makes the driver model PM suspend debug messages more useful, by

  (a) explaining what event is being sent, since not all suspend()
      requests mean the same thing;

  (b) reporting when a PM_EVENT_SUSPEND call is allowing the device
      to issue wakeup events.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>