r600g: add script to generate header file with offsets into state objects.

r600g: add script to generate header file with offsets into state objects.

This was inherently fragile as any changes to r600_states.h would also
need manual updating of all of the bits in radeon.h. Just add a simple
python script to do the conversion, its not hooked up to make at all.

This also will make adding evergreen a bit easier.