PCH Direct eSPI Reset Handling

When the PCH eSPI controller ESPI_​RESET# asserts, the PCH Direct eSPI target resets its entire eSPI interface-related logic. Before ESPI_​RESET# assertion, the processor issues a PLTRST# assertion VW over the Direct eSPI interface. The PCH Direct eSPI target uses this VW for reset isolation from the rest of the eSPI controller, which is available on the early boot side reset domain. Once isolation is completed, the PCH Direct eSPI target forwards PLTRST# assertion VW to PCH PMC. The ESPI_​RESET# assertion occurs after the PLTRST# assertion VW received by the PCH.