pinctrl: amd: fix error return code in amd_gpio_probe()

platform_get_irq() returns an error code, but the pinctrl-amd driver
ignores it and always returns -EINVAL. This is not correct and,
prevents -EPROBE_DEFER from being propagated properly.

Print and propagate the return value of platform_get_irq on failure.

This issue was detected with the help of Coccinelle.
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/pinctrl-amd.c

@@ -760,8 +760,8 @@ static int amd_gpio_probe(struct platform_device *pdev)
 
 	irq_base = platform_get_irq(pdev, 0);
 	if (irq_base < 0) {
-		dev_err(&pdev->dev, "Failed to get gpio IRQ.\n");
-		return -EINVAL;
+		dev_err(&pdev->dev, "Failed to get gpio IRQ: %d\n", irq_base);
+		return irq_base;
 	}
 
 	gpio_dev->pdev = pdev;