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: Shobhit Kumar <shobhit.kumar@intel.com>
Cc: Zhu, Lejun <lejun.zhu@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>