[SeaBIOS] [PATCH] geodevga: make use of readl and writel for mmio access

[ron minnich]

Memory slowly returns.

The "key idea" of the geode was that certain hardware was implemented
in the very complex software that is always running underneath. Hence,
many registers are always virtual. Hence, certain types of register
writes trigger SMI-like behaviour.

I'd be very careful about messing with this code.

ron