cgroup: fix function name in comment

Function name cgroup_rstat_cpu_pop_upated() in comment should be
cgroup_rstat_cpu_pop_updated().
Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

kernel/cgroup/rstat.c

@@ -33,7 +33,7 @@ void cgroup_rstat_updated(struct cgroup *cgrp, int cpu)
 		return;
 
 	/*
-	 * Paired with the one in cgroup_rstat_cpu_pop_upated().  Either we
+	 * Paired with the one in cgroup_rstat_cpu_pop_updated().  Either we
 	 * see NULL updated_next or they see our updated stat.
 	 */
 	smp_mb();