[coreboot] legacy bios support and coreboot

[Myles Watson]

> I've written a loader for coreboot-v2 to load legacybios, it works
> well when used with qemu, I've booted freebsd with it. But on real
> hardware, via epia-cn, it hangs with a blank screen, the debug port
> value is 0x31, I'll take some time to see what's going wrong.
> 
> I add a header for legacybios to become a payload, this is done by a
> utility createpayload.
> I've attached the loader and the utility.
> Signed-off-by: Aaron Lwe <aaron.lwe at gmail.com>

It seems like it would be fairly easy to make this compile as a normal ELF
payload, and thus be able to use it with v3 as well.  Have you thought about
the pros and cons?

Thanks,
Myles