Microchip: MEC172x: I2C driver

Microchip MEC172x series I2C driver implementing controller
and target modes. The driver implemenents its own I2C port
pin control functions and does not depended upon pinmux. Future
updates will make use of PINCTRL when that subystem is finalized.

Signed-off-by: Scott Worley <scott.worley@microchip.com>