gpio: fix doc string for devm_gpiochip_add_data() to not talk about irq_chip

The function is about adding a gpio_chip so dev has to belong to this
one. Fix wording to be more grammatically correct (but attention, I'm
not a native speaker).
Signed-off-by: Uwe Kleine-König <uwe@kleine-koenig.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpiolib.c

@@ -1525,7 +1525,7 @@ static int devm_gpio_chip_match(struct device *dev, void *res, void *data)
 
 /**
  * devm_gpiochip_add_data() - Resource manager gpiochip_add_data()
- * @dev: the device pointer on which irq_chip belongs to.
+ * @dev: pointer to the device that gpio_chip belongs to.
  * @chip: the chip to register, with chip->base initialized
  * @data: driver-private data associated with this chip
  *