gpio: tangier: Introduce Intel Tangier GPIO driver

Intel Elkhart Lake and Merrifield platforms have same GPIO IP.
Intel Tangier implements the common GPIO functionalities for both
Elkhart Lake and Merrifield platforms.

Signed-off-by: Pandith N <pandith.n@intel.com>
Co-developed-by: Raag Jadav <raag.jadav@intel.com>
Signed-off-by: Raag Jadav <raag.jadav@intel.com>
Co-developed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>