[coreboot] [PATCH][cbv2]Add serial port information to lbtable

[Patrick Georgi]

Hi,

the attached patch makes cbv2 add information about the serial port to
lbtable. For this, a new record type is created. Payloads can then parse
lbtable to figure out where to find the serial port (which is usually
used by lb as console already).

A patch for grub2 exists, too, and I'll implement a compatible change
for cbv3 once the record format (and overall design etc) is stable.

Regards,
Patrick Georgi