[GEODE] Add framebuffer support for the AMD Geode LX

I sent this out a few weeks ago, but I didn't hear anything back - so I'll
give it another shot now that .22 is in the can.  This is a basic driver
adding support for the AMD Geode LX framebuffer.  More advanced features,
such as acceleration and power management will come along later after they
have had a chance to soak a little bit more in the OLPC tree.

Jordan