pinctrl: amd: isp411: Fix IS_ERR() vs NULL check in probe()

The platform_get_resource() returns NULL on error.  It doesn't
return error pointers.  Fix the error checking to match.

Fixes: e97435a ("pinctrl: amd: isp411: Add amdisp GPIO pinctrl")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Pratap Nirujogi <pratap.nirujogi@amd.com>
Link: https://lore.kernel.org/617f4c77-7837-4e24-9f4d-620ecfedf924@stanley.mountain
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

Author: Dan Carpenter

drivers/pinctrl/pinctrl-amdisp.c

@@ -183,8 +183,8 @@ static int amdisp_pinctrl_probe(struct platform_device *pdev)
 	pdev->dev.init_name = DRV_NAME;
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	if (IS_ERR(res))
-		return PTR_ERR(res);
+	if (!res)
+		return -EINVAL;
 
 	pctrl->gpiobase = devm_ioremap_resource(&pdev->dev, res);
 	if (IS_ERR(pctrl->gpiobase))