gpiolib: add support for scope-based management to gpio_device

As the few users that need to get the reference to the GPIO device often
release it right after inspecting its properties, let's add support for
the automatic reference release to struct gpio_device.
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

include/linux/gpio/driver.h

@@ -3,6 +3,8 @@
 #define __LINUX_GPIO_DRIVER_H
 
 #include <linux/bits.h>
+#include <linux/cleanup.h>
+#include <linux/err.h>
 #include <linux/irqchip/chained_irq.h>
 #include <linux/irqdomain.h>
 #include <linux/irqhandler.h>
@@ -609,6 +611,9 @@ struct gpio_chip *gpiochip_find(void *data,
 struct gpio_device *gpio_device_get(struct gpio_device *gdev);
 void gpio_device_put(struct gpio_device *gdev);
 
+DEFINE_FREE(gpio_device_put, struct gpio_device *,
+	    if (IS_ERR_OR_NULL(_T)) gpio_device_put(_T));
+
 bool gpiochip_line_is_irq(struct gpio_chip *gc, unsigned int offset);
 int gpiochip_reqres_irq(struct gpio_chip *gc, unsigned int offset);
 void gpiochip_relres_irq(struct gpio_chip *gc, unsigned int offset);