gpio_chip.free() is optional, and can just be left unimplemented.
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Acked-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: NLinus Walleij <linus.walleij@linaro.org>