pinctrl: ralink: rt2880: use 'PTR_ERR_OR_ZERO'

 Avoid some boilerplate code using 'PTR_ERR_OR_ZERO'
 in probe function.
Signed-off-by: Sergio Paracuellos <sergio.paracuellos@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20201213161721.6514-8-sergio.paracuellos@gmail.comSigned-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/ralink/pinctrl-rt2880.c

@@ -343,10 +343,8 @@ static int rt2880_pinmux_probe(struct platform_device *pdev)
 		return err;
 	}
 	dev = pinctrl_register(p->desc, &pdev->dev, p);
-	if (IS_ERR(dev))
-		return PTR_ERR(dev);
 
-	return 0;
+	return PTR_ERR_OR_ZERO(dev);
 }
 
 static const struct of_device_id rt2880_pinmux_match[] = {