cgroups: consolidate cgroup documents

Move Documentation/cpusets.txt and Documentation/controllers/* to
Documentation/cgroups/

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/res_counter.h b/include/linux/res_counter.h
index dede0a2..4c5bcf6 100644
--- a/include/linux/res_counter.h
+++ b/include/linux/res_counter.h
@@ -9,7 +9,7 @@
  *
  * Author: Pavel Emelianov <xemul@openvz.org>
  *
- * See Documentation/controllers/resource_counter.txt for more
+ * See Documentation/cgroups/resource_counter.txt for more
  * info about what this counter is.
  */