iommufd: Use iommu_paging_domain_alloc()

If the iommu driver doesn't implement its domain_alloc_user callback,
iommufd_hwpt_paging_alloc() rolls back to allocate an iommu paging domain.
Replace iommu_domain_alloc() with iommu_user_domain_alloc() to pass the
device pointer along the path.
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/20240610085555.88197-3-baolu.lu@linux.intel.comSigned-off-by: Will Deacon <will@kernel.org>

drivers/iommu/iommufd/hw_pagetable.c

@@ -137,9 +137,10 @@ iommufd_hwpt_paging_alloc(struct iommufd_ctx *ictx, struct iommufd_ioas *ioas,
 		}
 		hwpt->domain->owner = ops;
 	} else {
-		hwpt->domain = iommu_domain_alloc(idev->dev->bus);
-		if (!hwpt->domain) {
-			rc = -ENOMEM;
+		hwpt->domain = iommu_paging_domain_alloc(idev->dev);
+		if (IS_ERR(hwpt->domain)) {
+			rc = PTR_ERR(hwpt->domain);
+			hwpt->domain = NULL;
 			goto out_abort;
 		}
 	}