pinctrl: intel: Add Intel Sunrisepoint pin controller and GPIO support

This driver supports pinctrl/GPIO hardware found on Intel Sunrisepoint (a
Skylake PCH) providing users a pinctrl and GPIO interfaces (including GPIO
interrupts).

The driver is split into core and platform parts so that the same core
driver can be reused in other drivers for other Intel GPIO hardware that is
based on the same host controller design.

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