PCI: dwc: artpec6: Fix return value check in artpec6_add_pcie_ep()

In case of error, the function devm_ioremap() returns NULL pointer
not ERR_PTR(). The IS_ERR() test in the return value check should be
replaced with NULL test.
Signed-off-by: NWei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>

drivers/pci/dwc/pcie-artpec6.c

@@ -485,8 +485,8 @@ static int artpec6_add_pcie_ep(struct artpec6_pcie *artpec6_pcie,
 
 	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dbi2");
 	pci->dbi_base2 = devm_ioremap(dev, res->start, resource_size(res));
-	if (IS_ERR(pci->dbi_base2))
-		return PTR_ERR(pci->dbi_base2);
+	if (!pci->dbi_base2)
+		return -ENOMEM;
 
 	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "addr_space");
 	if (!res)