gpio: iop: fix devm_ioremap_resource() return value checking

devm_ioremap_resource() returns a pointer to the remapped memory or
an ERR_PTR() encoded error code on failure. Fix the check inside
iop3xx_gpio_probe() accordingly.

Cc: Lennert Buytenhek <[e-mail]>
Cc: Mikael Pettersson <[e-mail]>
Cc: Aaro Koskinen <[e-mail]>
Signed-off-by: Bartlomiej Zolnierkiewicz <[e-mail]>
Acked-by: Alexandre Courbot <[e-mail]>
Acked-by: Dan Williams <[e-mail]>
Signed-off-by: Linus Walleij <[e-mail]>

drivers/gpio/gpio-iop.c

···
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
 
 	return gpiochip_add(&iop3xx_chip);
 }