gpio/vt8500: Convert to devm_ioremap_resource()

Use the newly introduced devm_ioremap_resource() instead of
devm_request_and_ioremap() which provides more consistent error handling.

devm_ioremap_resource() provides its own error messages; so all explicit
error messages can be removed from the failure code paths.

Signed-off-by: Sachin Kamat <[e-mail]>
Reviewed-by: Thierry Reding <[e-mail]>
Acked-by: Tony Prisk <[e-mail]>
Signed-off-by: Linus Walleij <[e-mail]>

drivers/gpio/gpio-vt8500.c

···
 		return -ENODEV;
 	}
 
-	gpio_base = devm_request_and_ioremap(&pdev->dev, res);
-	if (!gpio_base) {
-		dev_err(&pdev->dev, "Unable to map GPIO registers\n");
-		return -ENOMEM;
-	}
+	gpio_base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(gpio_base))
+		return PTR_ERR(gpio_base);
 
 	ret = vt8500_add_chips(pdev, gpio_base, of_id->data);