[S390] guest page hinting light

Use the existing arch_alloc_page/arch_free_page callbacks to do
the guest page state transitions between stable and unused.

Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
index fa31de6..29f3a63 100644
--- a/arch/s390/mm/init.c
+++ b/arch/s390/mm/init.c
@@ -126,6 +126,9 @@
         /* clear the zero-page */
         memset(empty_zero_page, 0, PAGE_SIZE);
 
+	/* Setup guest page hinting */
+	cmma_init();
+
 	/* this will put all low memory onto the freelists */
 	totalram_pages += free_all_bootmem();