cgroup: fix obsolete comment above for_each_css()

cgroup_tree_mutex is removed since commit 8353da1f91 ("cgroup: remove
cgroup_tree_mutex"), update corresponding comment.

Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Miaohe Lin 2023-06-27 19:40:59 +08:00 • committed by Tejun Heo
commit 868f87b375