[coreboot] patch: add in smbus support for mcp55

[ron minnich]

This patch adds in a bit more support, this is the mcp55 smbus.

This also illustrates the need to figure out the pci stuff in a better
way. It works for now, but we need to do better.

But we'll figure out it once we have a full port under our belts, and
we can come up with something that works right. We're still
getting over the v2 practice of including .c files :-) [Which, lest we
forget, was the best way to do things given that we did NOT have
cache as ram -- I intend no criticism at all!]

Signed-off-by: Ronald G. Minnich