MAINTAINERS: Update Intel PMIC (MFD part) to Supported

The actual status of the code is Supported.

Reported-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20220530120015.70543-1-andriy.shevchenko@linux.intel.com