cgroup: fix memory leak in cgroup_mount()

We should free the memory allocated in parse_cgroupfs_options() before
calling this function again.

Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

kernel/cgroup.c

@@ -1540,6 +1540,8 @@ retry:
 		if (!atomic_inc_not_zero(&root->top_cgroup.refcnt)) {
 			mutex_unlock(&cgroup_mutex);
 			mutex_unlock(&cgroup_tree_mutex);
+			kfree(opts.release_agent);
+			kfree(opts.name);
 			msleep(10);
 			goto retry;
 		}