[PATCH] uswsusp: add pmops->{prepare,enter,finish} support (aka "platform mode")

Add an ioctl to the userspace swsusp code that enables the usage of the
pmops->prepare, pmops->enter and pmops->finish methods (the in-kernel
suspend knows these as "platform method").  These are needed on many
machines to (among others) speed up resuming by letting the BIOS skip some
steps or let my hp nx5000 recognise the correct ac_adapter state after
resume again.

It also ensures on many machines, that changed hardware (unplugged AC
adapters) gets correctly detected and that kacpid does not run wild after
resume.

Signed-off-by: Stefan Seyfried <seife@suse.de>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>