i965/gen6: Use the dynamic state base address to reduce relocations.

i965/gen6: Use the dynamic state base address to reduce relocations.

Now that all the dynamic state is streamed through the top of the
batchbuffer, we can cut out many of our relocations to that state by
using the base address.

Improves 3DMMES taiji performance 3.3% +/- 0.4% (n=15).

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>