[coreboot] [PATCH] Reduce duplicate definition in CAR code.

[ron minnich]

I think I'm happier if other newer commiters ack this stuff. I don't
work with the code frequently enough to feel comfortable acking some
of these things.

I'm very happy with macros that make data definitions clearer. I'm
very worried about assembly code macros because this is tricky
assembly and people fall into certain habits in terms of thinking
macros are side-effect-free, which they are not in this case.

thanks!

ron