mm,hwpoison: cleanup unused PageHuge() check

mainline inclusion
from linux-v5.10-rc1
commit 7d9d46ac
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I4LE22


CVE: NA

--------------------------------

Drop the PageHuge check, which is dead code since memory_failure() forks
into memory_failure_hugetlb() for hugetlb pages.

memory_failure() and memory_failure_hugetlb() shares some functions like
hwpoison_user_mappings() and identify_page_state(), so they should
properly handle 4kB page, thp, and hugetlb.

Signed-off-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Ma Wupeng <mawupeng1@huawei.com>
Reviewed-by: tong tiangen <tongtiangen@huawei.com>
Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>