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/onenand/onenand_base.c b/drivers/mtd/onenand/onenand_base.c
index a839473..dd278a2 100644
--- a/drivers/mtd/onenand/onenand_base.c
+++ b/drivers/mtd/onenand/onenand_base.c
@@ -2645,7 +2645,7 @@
 	}
 
 	onenand_get_device(mtd, FL_WRITING);
-	ret = this->block_markbad(mtd, ofs);
+	ret = mtd_block_markbad(mtd, ofs);
 	onenand_release_device(mtd);
 	return ret;
 }