gpu: host1x: Use iommu_paging_domain_alloc()

An iommu domain is allocated in host1x_iommu_attach() and is attached to
host->dev. Use iommu_paging_domain_alloc() to make it explicit.
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/20240610085555.88197-8-baolu.lu@linux.intel.comSigned-off-by: Thierry Reding <treding@nvidia.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240812071605.9513-1-baolu.lu@linux.intel.com

drivers/gpu/host1x/dev.c

@@ -404,9 +404,10 @@ static struct iommu_domain *host1x_iommu_attach(struct host1x *host)
 		if (err < 0)
 			goto put_group;
 
-		host->domain = iommu_domain_alloc(&platform_bus_type);
-		if (!host->domain) {
-			err = -ENOMEM;
+		host->domain = iommu_paging_domain_alloc(host->dev);
+		if (IS_ERR(host->domain)) {
+			err = PTR_ERR(host->domain);
+			host->domain = NULL;
 			goto put_cache;
 		}