pinctrl: Add pinmux & GPIO controller driver for a new SoC

Intel Lightning Mountain SoC has a pinmux controller & GPIO controller IP which
controls pin multiplexing & configuration including GPIO functions selection &
GPIO attributes configuration.

This IP is not based on & does not have anything in common with Chassis
specification. The pinctrl drivers under pinctrl/intel/* are all based upon
Chassis spec compliant pinctrl IPs. So this driver doesn't fit & can not use
pinctrl framework under pinctrl/intel/* and it requires a separate new driver.

Add a new GPIO & pin control framework based driver for this IP.

Signed-off-by: Rahul Tanwar <rahul.tanwar@linux.intel.com>
Link: https://lore.kernel.org/r/33e649758b70490f01724a887c490d5008c7656d.1573797249.git.rahul.tanwar@linux.intel.com
Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>