virtio-blk: free vblk-vqs in error path of virtblk_probe()

Else there will be memory leak if alloc_disk() fails.

Fixes: 6a27b656fc ("block: virtio-blk: support multi virt queues per virtio-blk device")
Signed-off-by: Hou Tao <houtao1@huawei.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drivers/block/virtio_blk.c

@@ -878,6 +878,7 @@ out_put_disk:
 	put_disk(vblk->disk);
 out_free_vq:
 	vdev->config->del_vqs(vdev);
+	kfree(vblk->vqs);
 out_free_vblk:
 	kfree(vblk);
 out_free_index: