make cgroup_enable_task_cg_lists() static

Make the needlessly global cgroup_enable_task_cg_lists() static.

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kernel/cgroup.c

@@ -1715,7 +1715,7 @@ static void cgroup_advance_iter(struct cgroup *cgrp,
  * The tasklist_lock is not held here, as do_each_thread() and
  * while_each_thread() are protected by RCU.
  */
-void cgroup_enable_task_cg_lists(void)
+static void cgroup_enable_task_cg_lists(void)
 {
 	struct task_struct *p, *g;
 	write_lock(&css_set_lock);