pinctrl: intel: Add Intel Broxton pin controller support

This driver adds pinctrl/GPIO support for Intel Broxton. The GPIO
controller is based on the same hardware design that is already used in
Intel Sunrisepoint so we leverage the core driver here.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>