vduse: refactor vdpa_dev_add for goto err handling

Next patches introduce more error paths in this function.  Refactor it
so they can be accommodated through gotos.

Acked-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Xie Yongji <xieyongji@bytedance.com>
Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <20260119143306.1818855-8-eperezma@redhat.com>

Author: eugpermar

drivers/vdpa/vdpa_user/vduse_dev.c

@@ -2171,21 +2171,27 @@ static int vdpa_dev_add(struct vdpa_mgmt_dev *mdev, const char *name,
 						  dev->bounce_size);
 	mutex_unlock(&dev->domain_lock);
 	if (!dev->domain) {
-		put_device(&dev->vdev->vdpa.dev);
-		return -ENOMEM;
+		ret = -ENOMEM;
+		goto domain_err;
 	}
 
 	ret = _vdpa_register_device(&dev->vdev->vdpa, dev->vq_num);
 	if (ret) {
-		put_device(&dev->vdev->vdpa.dev);
-		mutex_lock(&dev->domain_lock);
-		vduse_domain_destroy(dev->domain);
-		dev->domain = NULL;
-		mutex_unlock(&dev->domain_lock);
-		return ret;
+		goto register_err;
 	}
 
 	return 0;
+
+register_err:
+	mutex_lock(&dev->domain_lock);
+	vduse_domain_destroy(dev->domain);
+	dev->domain = NULL;
+	mutex_unlock(&dev->domain_lock);
+
+domain_err:
+	put_device(&dev->vdev->vdpa.dev);
+
+	return ret;
 }
 
 static void vdpa_dev_del(struct vdpa_mgmt_dev *mdev, struct vdpa_device *dev)