soc: fsl: qbman: Use iommu_paging_domain_alloc()

An iommu domain is allocated in portal_set_cpu() and is attached to
pcfg->dev in the same function.

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/20240610085555.88197-14-baolu.lu@linux.intel.comSigned-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>

drivers/soc/fsl/qbman/qman_portal.c

@@ -48,9 +48,10 @@ static void portal_set_cpu(struct qm_portal_config *pcfg, int cpu)
 	struct device *dev = pcfg->dev;
 	int ret;
 
-	pcfg->iommu_domain = iommu_domain_alloc(&platform_bus_type);
-	if (!pcfg->iommu_domain) {
+	pcfg->iommu_domain = iommu_paging_domain_alloc(dev);
+	if (IS_ERR(pcfg->iommu_domain)) {
 		dev_err(dev, "%s(): iommu_domain_alloc() failed", __func__);
+		pcfg->iommu_domain = NULL;
 		goto no_iommu;
 	}
 	ret = fsl_pamu_configure_l1_stash(pcfg->iommu_domain, cpu);