virtio-mmio: Use PTR_ERR_OR_ZERO()

Fix ptr_ret.cocci warnings:
drivers/virtio/virtio_mmio.c:653:1-3: WARNING: PTR_ERR_OR_ZERO can be used

Use PTR_ERR_OR_ZERO rather than if(IS_ERR(...)) + PTR_ERR

Generated by: scripts/coccinelle/api/ptr_ret.cocci
Signed-off-by: NVasyl Gomonovych <gomonovych@gmail.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

drivers/virtio/virtio_mmio.c

@@ -662,10 +662,8 @@ static int vm_cmdline_set(const char *device,
 	pdev = platform_device_register_resndata(&vm_cmdline_parent,
 			"virtio-mmio", vm_cmdline_id++,
 			resources, ARRAY_SIZE(resources), NULL, 0);
-	if (IS_ERR(pdev))
-		return PTR_ERR(pdev);
 
-	return 0;
+	return PTR_ERR_OR_ZERO(pdev);
 }
 
 static int vm_cmdline_get_device(struct device *dev, void *data)