PM / Hibernate: Compress hibernation image with LZO

Compress hibernation image with LZO in order to save on I/O and
therefore time to hibernate/thaw.

[rjw: Added hibernate=nocompress command line option instead of just
 nocompress which would be confusing, fixed a couple of compiler
 warnings, fixed kerneldoc comments, minor cleanups.]

Signed-off-by: Bojan Smojver <bojan@rexursive.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

kernel/power/power.h

@@ -134,6 +134,7 @@ extern int swsusp_swap_in_use(void);
  * the image header.
  */
 #define SF_PLATFORM_MODE	1
+#define SF_NOCOMPRESS_MODE	2
 
 /* kernel/power/hibernate.c */
 extern int swsusp_check(void);