mm: add new arch_make_huge_pte() method for tile support

The tile support for multiple-size huge pages requires tagging
the hugetlb PTE with a "super" bit for PTEs that are multiples of
the basic size of a pagetable span.  To set that bit properly
we need to tweak the PTe in make_huge_pte() based on the vma.

This change provides the API for a subsequent tile-specific
change to use.

Reviewed-by: Hillf Danton <dhillf@gmail.com>
Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index ae8f708..4e28416 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2213,6 +2213,7 @@
 	}
 	entry = pte_mkyoung(entry);
 	entry = pte_mkhuge(entry);
+	entry = arch_make_huge_pte(entry, vma, page, writable);
 
 	return entry;
 }