[coreboot] patch: init gx cache earlier.

[ron minnich]

I think this is fine but I'd like to fit it into the "stage"
nomenclature, so the numbering fits.

So which stage is this? I am not sure, I feel like the stage numbering
never quite got finished :-)

possibly stage 3 is load payload, stage 4 is prepare the machine for a
payload, and stage5 is run the payload?

ron