mtip32xx: add error handling support for add_disk()

We never checked for errors on add_disk() as this function
returned void. Now that this is fixed, use the shiny new
error handling.

The read_capacity_error error label already does what we need,
so just re-use that.

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drivers/block/mtip32xx/mtip32xx.c

@@ -3633,7 +3633,9 @@ static int mtip_block_initialize(struct driver_data *dd)
 	set_capacity(dd->disk, capacity);
 
 	/* Enable the block device and add it to /dev */
-	device_add_disk(&dd->pdev->dev, dd->disk, mtip_disk_attr_groups);
+	rv = device_add_disk(&dd->pdev->dev, dd->disk, mtip_disk_attr_groups);
+	if (rv)
+		goto read_capacity_error;
 
 	if (dd->mtip_svc_handler) {
 		set_bit(MTIP_DDF_INIT_DONE_BIT, &dd->dd_flag);