mtd: introduce mtd_block_markbad 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/mtdswap.c b/drivers/mtd/mtdswap.c
index 87aa0a6..4441c08 100644
--- a/drivers/mtd/mtdswap.c
+++ b/drivers/mtd/mtdswap.c
@@ -279,7 +279,7 @@
 
 	offset = mtdswap_eb_offset(d, eb);
 	dev_warn(d->dev, "Marking bad block at %08llx\n", offset);
-	ret = d->mtd->block_markbad(d->mtd, offset);
+	ret = mtd_block_markbad(d->mtd, offset);
 
 	if (ret) {
 		dev_warn(d->dev, "Mark block bad failed for block at %08llx "