mtd: introduce mtd_resume interface

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/sa1100-flash.c b/drivers/mtd/maps/sa1100-flash.c
index 20944f0..5028219 100644
--- a/drivers/mtd/maps/sa1100-flash.c
+++ b/drivers/mtd/maps/sa1100-flash.c
@@ -378,7 +378,7 @@
 {
 	struct sa_info *info = platform_get_drvdata(dev);
 	if (info && mtd_suspend(info->mtd) == 0)
-		info->mtd->resume(info->mtd);
+		mtd_resume(info->mtd);
 }
 #else
 #define sa1100_mtd_shutdown NULL