RDMA/usnic: Use iommu_paging_domain_alloc()

usnic_uiom_alloc_pd() allocates a paging domain for a given device.
In this case, iommu_domain_alloc(dev->bus) is equivalent to 
iommu_paging_domain_alloc(dev). Replace it as iommu_domain_alloc()
has been deprecated.
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Acked-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/20240610085555.88197-15-baolu.lu@linux.intel.comSigned-off-by: Will Deacon <will@kernel.org>

drivers/infiniband/hw/usnic/usnic_uiom.c

@@ -443,11 +443,11 @@ struct usnic_uiom_pd *usnic_uiom_alloc_pd(struct device *dev)
 	if (!pd)
 		return ERR_PTR(-ENOMEM);
 
-	pd->domain = domain = iommu_domain_alloc(dev->bus);
-	if (!domain) {
+	pd->domain = domain = iommu_paging_domain_alloc(dev);
+	if (IS_ERR(domain)) {
 		usnic_err("Failed to allocate IOMMU domain");
 		kfree(pd);
-		return ERR_PTR(-ENOMEM);
+		return ERR_CAST(domain);
 	}
 
 	iommu_set_fault_handler(pd->domain, usnic_uiom_dma_fault, NULL);