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-loongson.c b/drivers/gpio/gpio-loongson.c
index ccc65a1..92c4fe7 100644
--- a/drivers/gpio/gpio-loongson.c
+++ b/drivers/gpio/gpio-loongson.c
@@ -110,6 +110,6 @@
 
 static int __init loongson_gpio_setup(void)
 {
-	return gpiochip_add(&loongson_chip);
+	return gpiochip_add_data(&loongson_chip, NULL);
 }
 postcore_initcall(loongson_gpio_setup);