gpio: constify opaque pointer "data" in gpio_device_find()

The opaque pointer "data" in each match function used by
gpio_device_find() is a pointer to const, thus the same argument passed
to gpio_device_find() can adjusted similarly.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Author: krzk

drivers/gpio/gpiolib.c

@@ -1171,7 +1171,7 @@ EXPORT_SYMBOL_GPL(gpiochip_remove);
  * If the function returns non-NULL, the returned reference must be freed by
  * the caller using gpio_device_put().
  */
-struct gpio_device *gpio_device_find(void *data,
+struct gpio_device *gpio_device_find(const void *data,
 				     int (*match)(struct gpio_chip *gc,
 						  const void *data))
 {

include/linux/gpio/driver.h

@@ -628,7 +628,7 @@ int devm_gpiochip_add_data_with_key(struct device *dev, struct gpio_chip *gc,
 				    void *data, struct lock_class_key *lock_key,
 				    struct lock_class_key *request_key);
 
-struct gpio_device *gpio_device_find(void *data,
+struct gpio_device *gpio_device_find(const void *data,
 				int (*match)(struct gpio_chip *gc,
 					     const void *data));
 struct gpio_device *gpio_device_find_by_label(const char *label);