mm: Add is_cma_pageblock definition

Bring back the is_cma_pageblock definition for determining if a
page is CMA or not.

Change-Id: I39fd546e22e240b752244832c79514f109c8e84b
Signed-off-by: Laura Abbott <lauraa@codeaurora.org>
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index ec88a36..3bed6fb 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -758,6 +758,11 @@
 }
 
 #ifdef CONFIG_CMA
+bool is_cma_pageblock(struct page *page)
+{
+	return get_pageblock_migratetype(page) == MIGRATE_CMA;
+}
+
 /* Free whole pageblock and set it's migration type to MIGRATE_CMA. */
 void __init init_cma_reserved_pageblock(struct page *page)
 {