pinctrl: Add Intel Cherryview/Braswell pin controller support

This driver supports the pin/GPIO controllers found in newer Intel SoCs
like Cherryview and Braswell. The driver provides full GPIO support and
minimal set of pin controlling funtionality.

The driver is based on the original Cherryview GPIO driver authored by Ning
Li and Alan Cox.

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