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/nand/nandsim.c b/drivers/mtd/nand/nandsim.c
index 34c03be..261f478 100644
--- a/drivers/mtd/nand/nandsim.c
+++ b/drivers/mtd/nand/nandsim.c
@@ -737,7 +737,7 @@
 			return -EINVAL;
 		}
 		offset = erase_block_no * ns->geom.secsz;
-		if (mtd->block_markbad(mtd, offset)) {
+		if (mtd_block_markbad(mtd, offset)) {
 			NS_ERR("invalid badblocks.\n");
 			return -EINVAL;
 		}