[coreboot] Support for new serial console boards

[ratatouille gamer]

Coreboot have just a support for PCIe OXPCIe952 card and it's complete
deprecated and old board. the price of uart boards compatible with
coreboot, have a complete expensive price and all is used.
All these problems, that makes hard to use coreboot with Serial console.
Serial console use can help computer without compatibility of USB EMbedded
Controller Console.
Serial console is complete important for both old and new boards ports and
fixes.
Please if coreboot can support new cheap common serial console PCIe boards
in future, it's can be great for future ports and fixes in olders boards
include in the use for best 64BIT coreboot table support in the most boards.