mtd: mtdblock: test return value of add_mtd_blktrans_dev, because if can fail

This prevents a memory leak

Signed-off-by: Maxim Levitsky <maximlevitsky@gmail.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
diff --git a/drivers/mtd/mtdblock.c b/drivers/mtd/mtdblock.c
index 8e5da1e..7ce30a2 100644
--- a/drivers/mtd/mtdblock.c
+++ b/drivers/mtd/mtdblock.c
@@ -348,7 +348,8 @@
 	if (!(mtd->flags & MTD_WRITEABLE))
 		dev->mbd.readonly = 1;
 
-	add_mtd_blktrans_dev(&dev->mbd);
+	if (add_mtd_blktrans_dev(&dev->mbd))
+		kfree(dev);
 }
 
 static void mtdblock_remove_dev(struct mtd_blktrans_dev *dev)