This makes the driver use the data pointer added to the gpio_chip
to store a pointer to the state container instead of relying on
container_of().

Cc: Ulrich Hecht <ulrich.hecht+renesas@gmail.com>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Hisashi Nakamura <hisashi.nakamura.ak@renesas.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>