fix XEN_SAVE_RESTORE Kconfig dependencies

Make XEN_SAVE_RESTORE select HIBERNATE_CALLBACKS.
Remove XEN_SAVE_RESTORE dependency from PM_SLEEP.

Signed-off-by: Shriram Rajagopalan <rshriram@cs.ubc.ca>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

kernel/power/Kconfig

@@ -89,7 +89,7 @@ config PM_STD_PARTITION
 
 config PM_SLEEP
 	def_bool y
-	depends on SUSPEND || HIBERNATE_CALLBACKS || XEN_SAVE_RESTORE
+	depends on SUSPEND || HIBERNATE_CALLBACKS
 
 config PM_SLEEP_SMP
 	def_bool y