device_cgroup: Fix typo in devcgroup_css_alloc description

Fix the stale cgroup.c path in the devcgroup_css_alloc() description.
Signed-off-by: Kamalesh Babulal <kamalesh.babulal@oracle.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>

security/device_cgroup.c

@@ -216,7 +216,7 @@ static void devcgroup_offline(struct cgroup_subsys_state *css)
 }
 
 /*
- * called from kernel/cgroup.c with cgroup_lock() held.
+ * called from kernel/cgroup/cgroup.c with cgroup_lock() held.
  */
 static struct cgroup_subsys_state *
 devcgroup_css_alloc(struct cgroup_subsys_state *parent_css)