gpio: pxa: Fix return value of pxa_gpio_probe()

When call function devm_platform_ioremap_resource(), we should use IS_ERR()
to check the return value and return PTR_ERR() if failed.

Fixes: 542c25b7a2 ("drivers: gpio: pxa: use devm_platform_ioremap_resource()")
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>

drivers/gpio/gpio-pxa.c

@@ -660,8 +660,8 @@ static int pxa_gpio_probe(struct platform_device *pdev)
 	pchip->irq1 = irq1;
 
 	gpio_reg_base = devm_platform_ioremap_resource(pdev, 0);
-	if (!gpio_reg_base)
-		return -EINVAL;
+	if (IS_ERR(gpio_reg_base))
+		return PTR_ERR(gpio_reg_base);
 
 	clk = clk_get(&pdev->dev, NULL);
 	if (IS_ERR(clk)) {