pinctrl: lynxpoint: Add pin control operations

pinctrl: lynxpoint: Add pin control operations

Add implementation for:
    - pin control, group information retrieval: count, name and pins
    - pin muxing:
      - function information (count, name and groups)
      - mux setting
      - GPIO control (enable, disable, set direction)
    - pin configuration:
      - pull disable, up and down
      - any other option is treated as not supported.

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>