Add orig_pmd to struct vm_fault so the "orig_pmd" parameter used by huge page
fault could be removed, just like its PTE counterpart does.

Signed-off-by: Yang Shi <redacted>

<SNIP>

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 25b9041f9925..9c5856f8cc81 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h

@@ -547,6 +547,9 @@ struct vm_fault {
 					 * the 'address'
 					 */
 	pte_t orig_pte;			/* Value of PTE at the time of fault */
+	pmd_t orig_pmd;			/* Value of PMD at the time of fault,
+					 * used by PMD fault only.
+					 */
 
 	struct page *cow_page;		/* Page handler may use for COW fault */
 	struct page *page;		/* ->fault handlers should return a