leds: tca6507: use gpiochip data pointer

This makes the driver use the data pointer added to the gpio_chip
to store a pointer to the state container instead of relying on
container_of().

Cc: Riku Voipio <[e-mail]>
Cc: Richard Purdie <[e-mail]>
Cc: [e-mail]
Acked-by: Jacek Anaszewski <[e-mail]>
Signed-off-by: Linus Walleij <[e-mail]>

drivers/leds/leds-tca6507.c

···
 static void tca6507_gpio_set_value(struct gpio_chip *gc,
 				   unsigned offset, int val)
 {
-	struct tca6507_chip *tca = container_of(gc, struct tca6507_chip, gpio);
+	struct tca6507_chip *tca = gpiochip_get_data(gc);
 	unsigned long flags;
 
 	spin_lock_irqsave(&tca->lock, flags);
···
 #ifdef CONFIG_OF_GPIO
 	tca->gpio.of_node = of_node_get(client->dev.of_node);
 #endif
-	err = gpiochip_add(&tca->gpio);
+	err = gpiochip_add_data(&tca->gpio, tca);
 	if (err) {
 		tca->gpio.ngpio = 0;
 		return err;