[PATCH] swsusp: rework image freeing

The following patch makes swsusp use PG_nosave and PG_nosave_free flags to
mark pages that should be freed after the state of the system has been
restored from the image (or in case of an error during suspend).

This allows us to avoid storing metadata in swap twice and to reduce the
amount of memory needed by swsusp.   Additionally, it allows us to simplify
the code by removing a couple of functions that are no longer necessary.

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