PCI: mvebu: Convert to use devm_ioremap_resource

Commit 75096579 ("lib: devres: Introduce devm_ioremap_resource()")
introduced devm_ioremap_resource() and deprecated the use of
devm_request_and_ioremap().

While at it, modify mvebu_pcie_map_registers() to propagate error code.
Signed-off-by: Tushar Behera <tushar.behera@linaro.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>

drivers/pci/host/pci-mvebu.c

@@ -750,9 +750,9 @@ mvebu_pcie_map_registers(struct platform_device *pdev,
 
 	ret = of_address_to_resource(np, 0, &regs);
 	if (ret)
-		return NULL;
+		return ERR_PTR(ret);
 
-	return devm_request_and_ioremap(&pdev->dev, &regs);
+	return devm_ioremap_resource(&pdev->dev, &regs);
 }
 
 static int __init mvebu_pcie_probe(struct platform_device *pdev)
@@ -842,9 +842,10 @@ static int __init mvebu_pcie_probe(struct platform_device *pdev)
 			continue;
 
 		port->base = mvebu_pcie_map_registers(pdev, child, port);
-		if (!port->base) {
+		if (IS_ERR(port->base)) {
 			dev_err(&pdev->dev, "PCIe%d.%d: cannot map registers\n",
 				port->port, port->lane);
+			port->base = NULL;
 			continue;
 		}