[coreboot] coreboot+seabios+gpxe success

[Kevin O'Connor]

FYI,

I successfully built a coreboot-v2 image with both SeaBIOS and gpxe.
I concatenated the coreboot image, the video bios, and gpxe rom into
one big image and wrote it to flash.  I also told SeaBIOS how to
deploy the roms:

#define OPTIONROM_BDF_1 0x0100
#define OPTIONROM_MEM_1 0xfffc0000
#define OPTIONROM_BDF_2 0x0048
#define OPTIONROM_MEM_2 0xfffcf800

It works!

SeaBIOS support for option roms is pretty good, so this isn't very
surprising.  However, it is worth pointing out, because it shows that
an open source bios can match the functionality of a typical COTS
bios.

-Kevin