fix broken/dubious driver suspend() methods

Small driver suspend() fixes in preparation for the PRETHAW events:

 - Only compare message events for equality against PM_EVENT_* codes;
   not against integers, or using greater/less-than comparisons.
   (PM_EVENT_* should really become a __bitwise thing.)

 - Explicitly test for SUSPEND events (rather than not-something-else)
   before suspending devices.

 - Removes more of the confusion between a pm_message_t (wraps event code)
   and a "state" ... suspend() originally took a target system state.

These updates are correct and appropriate even without new PM_EVENT codes.

benh: "I think in the Mesh case, we should handle the freeze case as well or
we might get wild DMA."

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Acked-by: Pavel Machek <pavel@ucw.cz>
Cc: Greg KH <greg@kroah.com>
Cc: Paul Mackerras <paulus@samba.org>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Mauro Carvalho Chehab <mchehab@infradead.org>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>