gpiolib: remove stray newline in gpio/driver.h

Fix a double newline in the GPIO provider header.
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

include/linux/gpio/driver.h

@@ -764,7 +764,6 @@ void gpiochip_free_own_desc(struct gpio_desc *desc);
 int gpiochip_lock_as_irq(struct gpio_chip *gc, unsigned int offset);
 void gpiochip_unlock_as_irq(struct gpio_chip *gc, unsigned int offset);
 
-
 struct gpio_chip *gpiod_to_chip(const struct gpio_desc *desc);
 
 #else /* CONFIG_GPIOLIB */