mtd: convert remaining users to mtd_device_register()

The older add_mtd_device()/add_mtd_partitions() and their removal
counterparts will soon be gone.  Replace uses with mtd_device_register()
and mtd_device_unregister().

Signed-off-by: Jamie Iles <jamie@jamieiles.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.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 893d95b..357e8c5 100644
--- a/drivers/mtd/nand/nandsim.c
+++ b/drivers/mtd/nand/nandsim.c
@@ -2383,7 +2383,9 @@
 		goto err_exit;
 
 	/* Register NAND partitions */
-	if ((retval = add_mtd_partitions(nsmtd, &nand->partitions[0], nand->nbparts)) != 0)
+	retval = mtd_device_register(nsmtd, &nand->partitions[0],
+				     nand->nbparts);
+	if (retval != 0)
 		goto err_exit;
 
         return 0;