mtd: do not use mtd->suspend and mtd->resume directly

Just call the 'mtd_suspend()' and 'mtd_resume()' - they will do nothing
if the operation is not defined.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
diff --git a/drivers/mtd/maps/rbtx4939-flash.c b/drivers/mtd/maps/rbtx4939-flash.c
index 7176283..3da63fc 100644
--- a/drivers/mtd/maps/rbtx4939-flash.c
+++ b/drivers/mtd/maps/rbtx4939-flash.c
@@ -119,9 +119,8 @@
 {
 	struct rbtx4939_flash_info *info = platform_get_drvdata(dev);
 
-	if (info->mtd->suspend && info->mtd->resume)
-		if (mtd_suspend(info->mtd) == 0)
-			mtd_resume(info->mtd);
+	if (mtd_suspend(info->mtd) == 0)
+		mtd_resume(info->mtd);
 }
 #else
 #define rbtx4939_flash_shutdown NULL