Add the kernel command line parameter "resume_offset=" allowing us to specify
the offset, in <PAGE_SIZE> units, from the beginning of the partition pointed
to by the "resume=" parameter at which the swap header is located.

This offset can be determined, for example, by an application using the FIBMAP
ioctl to obtain the swap header's block number for given file.

[akpm@osdl.org: we don't know what type sector_t is]
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>
Cc: Pavel Machek <pavel@ucw.cz>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>