mm: memory-failure: add unmap_posioned_folio()

mm: memory-failure: add unmap_posioned_folio()

Add unmap_posioned_folio() helper which will be reused by
do_migrate_range() from memory hotplug soon.

Link: https://lkml.kernel.org/r/20240816090435.888946-3-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>