gpio: loongson1: remove redundant return value check

Remove unneeded error handling on the result of a call
to platform_get_resource() when the value is passed to
devm_ioremap_resource().

Signed-off-by: Wei Yongjun <[e-mail]>
Signed-off-by: Linus Walleij <[e-mail]>

drivers/gpio/gpio-loongson1.c

···
 		return -ENOMEM;
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	if (!res) {
-		dev_err(dev, "failed to get I/O memory\n");
-		return -EINVAL;
-	}
-
 	gpio_reg_base = devm_ioremap_resource(dev, res);
 	if (IS_ERR(gpio_reg_base))
 		return PTR_ERR(gpio_reg_base);