iommu/amd: Missing error code in amd_iommu_init_device()

BugLink: http://bugs.launchpad.net/bugs/1655969

commit 24c790fb upstream.

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

Fixes: 55c99a4d ("iommu/amd: Use iommu_attach_group()")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

drivers/iommu/amd_iommu_v2.c

@@ -809,8 +809,10 @@ 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)