block: genhd: add 'groups' argument to device_add_disk

Update device_add_disk() to take an 'groups' argument so that
individual drivers can register a device with additional sysfs
attributes.
This avoids race condition the driver would otherwise have if these
groups were to be created with sysfs_add_groups().

Signed-off-by: Martin Wilck <martin.wilck@suse.com>
Signed-off-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/drivers/block/mtip32xx/mtip32xx.c b/drivers/block/mtip32xx/mtip32xx.c
index d0666f5c..1d7d48d 100644
--- a/drivers/block/mtip32xx/mtip32xx.c
+++ b/drivers/block/mtip32xx/mtip32xx.c
@@ -3861,7 +3861,7 @@ 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);
+	device_add_disk(&dd->pdev->dev, dd->disk, NULL);
 
 	dd->bdev = bdget_disk(dd->disk, 0);
 	/*