[PATCH] swsusp: add ioctl for swap files support

To be able to use swap files as suspend storage from the userland suspend
tools we need an additional ioctl() that will allow us to provide the kernel
with both the swap header's offset and the identification of the resume
partition.

The new ioctl() should be regarded as a replacement for the
SNAPSHOT_SET_SWAP_FILE ioctl() that from now on will be considered as
obsolete, but has to stay for backwards compatibility of the interface.

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