pinctrl: nuvoton: Fix return value check in wpcm450_gpio_register()

In case of error, the function devm_platform_ioremap_resource()
returns ERR_PTR() and never returns NULL. The NULL test in the
return value check should be replaced with IS_ERR().

Fixes: a1d1e0e3 ("pinctrl: nuvoton: Add driver for WPCM450")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Jialin Zhang <zhangjialin11@huawei.com>
Reviewed-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Link: https://lore.kernel.org/r/20220317065851.495394-1-zhangjialin11@huawei.comSigned-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/nuvoton/pinctrl-wpcm450.c

@@ -1019,8 +1019,9 @@ static int wpcm450_gpio_register(struct platform_device *pdev,
 	int ret;
 
 	pctrl->gpio_base = devm_platform_ioremap_resource(pdev, 0);
-	if (!pctrl->gpio_base)
-		return dev_err_probe(dev, -ENOMEM, "Resource fail for GPIO controller\n");
+	if (IS_ERR(pctrl->gpio_base))
+		return dev_err_probe(dev, PTR_ERR(pctrl->gpio_base),
+				     "Resource fail for GPIO controller\n");
 
 	device_for_each_child_node(dev, child)  {
 		void __iomem *dat = NULL;