MAINTAINERS: Update Intel GPIO (PMIC and PCH) to Supported

The actual status of the code is Supported.

Reported-by:  <dave.hansen@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>