[Mesa-dev] i965 sampler state cleanups

[Kenneth Graunke]

A while back, I wrote a patch to skip border color upload, and got
annoyed by having to write it twice - once for the Gen4-6 code, and
once for Gen7+.  So I decided to clean that up.

23 patches and a bug fix later, I've unified the code, deleting
gen7_sampler_state.c entirely.  There's now one copy of the logic to
upload sampler state tables, and one copy of the logic that decides
what values to program.  Packet assembly now uses bitshifts instead
of structures, which is more consistent with the surface state code.

Tested with Piglit on Crestline, Sandybridge, and Haswell: no regressions.
The series is available as the 'sampler-cleanups' branch of my tree.