sched: correct sched-rt-group.txt pathname in init/Kconfig

init/Kconfig directs the user to Documentation/sched-rt-group.txt, but
the file is actually in Documentation/scheduler/sched-rt-group.txt.

This patch corrects the pathname mentioned in init/Kconfig.
Signed-off-by: NAdrian Knoth <adi@drcomp.erfurt.thur.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

init/Kconfig

@@ -354,7 +354,7 @@ config RT_GROUP_SCHED
 	  setting below. If enabled, it will also make it impossible to
 	  schedule realtime tasks for non-root users until you allocate
 	  realtime bandwidth for them.
-	  See Documentation/sched-rt-group.txt for more information.
+	  See Documentation/scheduler/sched-rt-group.txt for more information.
 
 choice
 	depends on GROUP_SCHED