mtd: introduce mtd_block_isbad 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/mtdoops.c b/drivers/mtd/mtdoops.c
index 7be2018..bc43d2f 100644
--- a/drivers/mtd/mtdoops.c
+++ b/drivers/mtd/mtdoops.c
@@ -170,7 +170,7 @@
 	}
 
 	while (mtd->block_isbad) {
-		ret = mtd->block_isbad(mtd, cxt->nextpage * record_size);
+		ret = mtd_block_isbad(mtd, cxt->nextpage * record_size);
 		if (!ret)
 			break;
 		if (ret < 0) {
@@ -254,7 +254,7 @@
 
 	for (page = 0; page < cxt->oops_pages; page++) {
 		if (mtd->block_isbad &&
-		    mtd->block_isbad(mtd, page * record_size))
+		    mtd_block_isbad(mtd, page * record_size))
 			continue;
 		/* Assume the page is used */
 		mark_page_used(cxt, page);