gpio: convert remaining users to gpiochip_add_data()

For completion, sweep the floor from all gpiochip_add() usage so
we can remove that function and get rid of the function wrapper
gpiochip_add().

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/drivers/gpio/gpio-xtensa.c b/drivers/gpio/gpio-xtensa.c
index 93ec95d..f16c042 100644
--- a/drivers/gpio/gpio-xtensa.c
+++ b/drivers/gpio/gpio-xtensa.c
@@ -148,10 +148,10 @@
 {
 	int ret;
 
-	ret = gpiochip_add(&impwire_chip);
+	ret = gpiochip_add_data(&impwire_chip, NULL);
 	if (ret)
 		return ret;
-	return gpiochip_add(&expstate_chip);
+	return gpiochip_add_data(&expstate_chip, NULL);
 }
 
 static struct platform_driver xtensa_gpio_driver = {