i965/drm: Remove some unused functions and macros.

i965/drm: Remove some unused functions and macros.

Mesa doesn't use these functions or macros, so we can delete them,
and save work refactoring and cleaning them up.  We'll delete a lot
more later, too.

Based on a patch by Kristian Høgsberg.

Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Acked-by: Jason Ekstrand <jason@jlekstrand.net>