iommu: Use __iommu_group_set_domain() in iommu_change_dev_def_domain()

This is missing re-attach error handling if the attach fails, use the
common code.

The ugly "group->domain = prev_domain" will be cleaned in a later patch.
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Tested-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/5-v5-1b99ae392328+44574-iommu_err_unwind_jgg@nvidia.comSigned-off-by: Joerg Roedel <jroedel@suse.de>

drivers/iommu/iommu.c

@@ -2946,11 +2946,12 @@ static int iommu_change_dev_def_domain(struct iommu_group *group,
 	if (ret)
 		goto restore_old_domain;
 
-	ret = iommu_group_create_direct_mappings(group);
+	group->domain = prev_dom;
+	ret = iommu_create_device_direct_mappings(group, dev);
 	if (ret)
 		goto free_new_domain;
 
-	ret = __iommu_attach_group(group->default_domain, group);
+	ret = __iommu_group_set_domain(group, group->default_domain);
 	if (ret)
 		goto free_new_domain;
 
@@ -2962,7 +2963,6 @@ static int iommu_change_dev_def_domain(struct iommu_group *group,
 	iommu_domain_free(group->default_domain);
 restore_old_domain:
 	group->default_domain = prev_dom;
-	group->domain = prev_dom;
 
 	return ret;
 }