This is a GPIO driver, use the appropriate header
<linux/gpio/driver.h> rather than the legacy <linux/gpio.h>
header.

Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>