[coreboot] SOC directory under src

[Aaron Durbin]

Hi folks,

I'm going to be working on a part that is an SOC. Because of this all
the traditional northbridge, southbridge, and cpu are tightly coupled.
Instead of splitting things out across those 3 directories I'm
inclined to create a 'soc' directory under src. All the related files
would fall under there:

src/soc/<vendor>/<soc_name>/...

It seems more logical to me, and as I'm sure you are all aware the
lines are quite a bit of inter-dependencies in products now-a-days.

I think/hope people won't too upset about this.

-Aaron