mm: memory-failure: use helper macro llist_for_each_entry_safe()

It's more convenient to use helper macro llist_for_each_entry_safe().
No functional change intended.

Link: https://lkml.kernel.org/r/20230807114125.3440802-1-linmiaohe@huawei.com


Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>