hwpoison: fix hugetlbfs/thp precheck in hwpoison_user_mappings()

hwpoison: fix hugetlbfs/thp precheck in hwpoison_user_mappings()

A recent fix from Chen Yucong, commit 0bc1f8b0682c ("hwpoison: fix the
handling path of the victimized page frame that belong to non-LRU")
rejects going into unmapping operation for hugetlbfs/thp pages, which
results in failing error containing on such pages.  This patch fixes it.

With this patch, hwpoison functional tests in mce-test testsuite pass.

Signed-off-by: Naoya Horiguchi <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: Chen Yucong <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>