[coreboot] v3 stage0

[Carl-Daniel Hailfinger]

Hi,

currently we have 3 different files with stage0 asm code sharing lots of
delicate code:
- amd/stage0.S
- geodelx/stage0.S
- stage0_i586.S
and all of them share at least the complete 16bit code which is near
unreadable in itself.

Can we extract the 16bit code into a common file and include it? I know
that choice isn't going to be too popular because it makes the code more
greppy. However, keeping all instances of that code in sync is a major
headache and we even have remaining bugs in the common copied 32bit
parts of that code.
If that's not possible, I'd like to at least enforce a rule which keeps
the common 16-bit code bit-for-bit identical including comments.

Regards,
Carl-Daniel