drm/rockchip: Use iommu_paging_domain_alloc()

Commit <421be3ee36a4> ("drm/rockchip: Refactor IOMMU initialisation") has
refactored rockchip_drm_init_iommu() to pass a device that the domain is
allocated for. Replace iommu_domain_alloc() with
iommu_paging_domain_alloc() to retire the former.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Acked-by: Andy Yan <andyshrk@163.com>
Signed-off-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240902014700.66095-3-baolu.lu@linux.intel.com

drivers/gpu/drm/rockchip/rockchip_drm_drv.c

@@ -103,13 +103,17 @@ static int rockchip_drm_init_iommu(struct drm_device *drm_dev)
 	struct rockchip_drm_private *private = drm_dev->dev_private;
 	struct iommu_domain_geometry *geometry;
 	u64 start, end;
+	int ret;
 
 	if (IS_ERR_OR_NULL(private->iommu_dev))
 		return 0;
 
-	private->domain = iommu_domain_alloc(private->iommu_dev->bus);
-	if (!private->domain)
-		return -ENOMEM;
+	private->domain = iommu_paging_domain_alloc(private->iommu_dev);
+	if (IS_ERR(private->domain)) {
+		ret = PTR_ERR(private->domain);
+		private->domain = NULL;
+		return ret;
+	}
 
 	geometry = &private->domain->geometry;
 	start = geometry->aperture_start;