um: virtio: free vu_dev only with the contained struct device

Since struct device is refcounted, we shouldn't free the vu_dev
immediately when it's removed from the platform device, but only
when the references actually all go away. Move the freeing to
the release to accomplish that.

Fixes: 5d38f324 ("um: drivers: Add virtio vhost-user driver")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

arch/um/drivers/virtio_uml.c

@@ -1084,6 +1084,7 @@ static void virtio_uml_release_dev(struct device *d)
 	}
 
 	os_close_file(vu_dev->sock);
+	kfree(vu_dev);
 }
 
 /* Platform device */
@@ -1097,7 +1098,7 @@ static int virtio_uml_probe(struct platform_device *pdev)
 	if (!pdata)
 		return -EINVAL;
 
-	vu_dev = devm_kzalloc(&pdev->dev, sizeof(*vu_dev), GFP_KERNEL);
+	vu_dev = kzalloc(sizeof(*vu_dev), GFP_KERNEL);
 	if (!vu_dev)
 		return -ENOMEM;