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/kernel/cpuset.c b/kernel/cpuset.c
index 647c77a..a856788 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -568,7 +568,7 @@
  * load balancing domains (sched domains) as specified by that partial
  * partition.
  *
- * See "What is sched_load_balance" in Documentation/cpusets.txt
+ * See "What is sched_load_balance" in Documentation/cgroups/cpusets.txt
  * for a background explanation of this.
  *
  * Does not return errors, on the theory that the callers of this