iommu/amd: Missing error code in amd_iommu_init_device()

We should set "ret" to -EINVAL if iommu_group_get() fails.

Fixes: 55c99a4dc50f ("iommu/amd: Use iommu_attach_group()")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
diff --git a/drivers/iommu/amd_iommu_v2.c b/drivers/iommu/amd_iommu_v2.c
index 594849a..f8ed8c9 100644
--- a/drivers/iommu/amd_iommu_v2.c
+++ b/drivers/iommu/amd_iommu_v2.c
@@ -805,8 +805,10 @@ int amd_iommu_init_device(struct pci_dev *pdev, int pasids)
 		goto out_free_domain;
 
 	group = iommu_group_get(&pdev->dev);
-	if (!group)
+	if (!group) {
+		ret = -EINVAL;
 		goto out_free_domain;
+	}
 
 	ret = iommu_attach_group(dev_state->domain, group);
 	if (ret != 0)