mtd: introduce mtd_is_locked 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/mtdchar.c b/drivers/mtd/mtdchar.c
index fe09cd2..6d598b23 100644
--- a/drivers/mtd/mtdchar.c
+++ b/drivers/mtd/mtdchar.c
@@ -852,7 +852,7 @@
 		if (!mtd->is_locked)
 			ret = -EOPNOTSUPP;
 		else
-			ret = mtd->is_locked(mtd, einfo.start, einfo.length);
+			ret = mtd_is_locked(mtd, einfo.start, einfo.length);
 		break;
 	}
 
diff --git a/drivers/mtd/mtdpart.c b/drivers/mtd/mtdpart.c
index d65af37..ad487fc 100644
--- a/drivers/mtd/mtdpart.c
+++ b/drivers/mtd/mtdpart.c
@@ -295,7 +295,7 @@
 	struct mtd_part *part = PART(mtd);
 	if ((len + ofs) > mtd->size)
 		return -EINVAL;
-	return part->master->is_locked(part->master, ofs + part->offset, len);
+	return mtd_is_locked(part->master, ofs + part->offset, len);
 }
 
 static void part_sync(struct mtd_info *mtd)