wifi: ath10k: Use iommu_paging_domain_alloc()

An iommu domain is allocated in ath10k_fw_init() and is attached to
ar_snoc->fw.dev in the same function. Use iommu_paging_domain_alloc() to
make it explicit.
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Acked-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/20240610085555.88197-11-baolu.lu@linux.intel.comSigned-off-by: Will Deacon <will@kernel.org>

drivers/net/wireless/ath/ath10k/snoc.c

@@ -1635,10 +1635,10 @@ static int ath10k_fw_init(struct ath10k *ar)
 
 	ar_snoc->fw.dev = &pdev->dev;
 
-	iommu_dom = iommu_domain_alloc(&platform_bus_type);
-	if (!iommu_dom) {
+	iommu_dom = iommu_paging_domain_alloc(ar_snoc->fw.dev);
+	if (IS_ERR(iommu_dom)) {
 		ath10k_err(ar, "failed to allocate iommu domain\n");
-		ret = -ENOMEM;
+		ret = PTR_ERR(iommu_dom);
 		goto err_unregister;
 	}