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/include/linux/mmzone.h b/include/linux/mmzone.h
index 08f74e6..2e5ce59 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -70,9 +70,11 @@
 extern int *get_migratetype_fallbacks(int mtype);
 
 #ifdef CONFIG_CMA
+bool is_cma_pageblock(struct page *page);
 #  define is_migrate_cma(migratetype) unlikely((migratetype) == MIGRATE_CMA)
 #  define cma_wmark_pages(zone)	zone->min_cma_pages
 #else
+#  define is_cma_pageblock(page) false
 #  define is_migrate_cma(migratetype) false
 #  define cma_wmark_pages(zone) 0
 #endif