pinctrl: Fix return value check in amd_gpio_probe()

In case of error, the function devm_ioremap_nocache() returns NULL
pointer not ERR_PTR(). The IS_ERR() test in the return value check
should be replaced with NULL test.

Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/drivers/pinctrl/pinctrl-amd.c b/drivers/pinctrl/pinctrl-amd.c
index 6574494..5c025f5 100644
--- a/drivers/pinctrl/pinctrl-amd.c
+++ b/drivers/pinctrl/pinctrl-amd.c
@@ -753,8 +753,8 @@
 
 	gpio_dev->base = devm_ioremap_nocache(&pdev->dev, res->start,
 						resource_size(res));
-	if (IS_ERR(gpio_dev->base))
-		return PTR_ERR(gpio_dev->base);
+	if (!gpio_dev->base)
+		return -ENOMEM;
 
 	irq_base = platform_get_irq(pdev, 0);
 	if (irq_base < 0) {