pinctrl: lantiq: remove bogus of_gpio_chip_add

Remove bogus call to of_gpiochip_add (and of_gpio_chip remove in error
path) which is also called when adding the gpio chip.

This prevents adding the same pinctrl range twice.

Fixes: 3f8c50c9 ("OF: pinctrl: MIPS: lantiq: implement lantiq/xway
pinctrl support")
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

(cherry picked from commit 41f632fe)
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>

drivers/pinctrl/pinctrl-xway.c

@@ -726,7 +726,6 @@ static int pinmux_xway_probe(struct platform_device *pdev)
 
 	/* load the gpio chip */
 	xway_chip.dev = &pdev->dev;
-	of_gpiochip_add(&xway_chip);
 	ret = gpiochip_add(&xway_chip);
 	if (ret) {
 		dev_err(&pdev->dev, "Failed to register gpio chip\n");