drivers: espi_saf: Add Microchip MEC172x eSPI SAF version 2 driver

Microchip MEC172x has a modified eSPI SAF hardware implementation.
Hardware changes include multiple clock dividers for each SPI
flash device and data transfer using QMSPI local DMA.
espi reset interrupt is made a higer priority in MEC172x devicetree
because espi reset event resets all espi hardware and we don't
to want to service any other espi interrupt blocks when espi reset
occurs.

Signed-off-by: Jay Vasanth <jay.vasanth@microchip.com>