s390/mm: fix addressing exception after suspend/resume

Commit c9b5ad546e7d "s390/mm: tag normal pages vs pages used in page tables"
accidentally changed the logic in arch_set_page_states(), which is used by
the suspend/resume code. set_page_stable(page, order) was changed to
set_page_stable_dat(page, 0). After this, only the first page of higher order
pages will be set to stable, and a write to one of the unstable pages will
result in an addressing exception.

Fix this by using "order" again, instead of "0".

Fixes: c9b5ad546e7d ("s390/mm: tag normal pages vs pages used in page tables")
Cc: stable@vger.kernel.org # 4.14+
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/mm/page-states.c

@@ -271,7 +271,7 @@ void arch_set_page_states(int make_stable)
 			list_for_each(l, &zone->free_area[order].free_list[t]) {
 				page = list_entry(l, struct page, lru);
 				if (make_stable)
-					set_page_stable_dat(page, 0);
+					set_page_stable_dat(page, order);
 				else
 					set_page_unused(page, order);
 			}