i965: Emit the depth/stencil state pointer directly, not via atoms.

i965: Emit the depth/stencil state pointer directly, not via atoms.

See two commits ago for the rationale.  This allows us to delete the
whole gen7_cc_state.c file.

This does move these commands before the depth stall flushes from
brw_emit_depthbuffer, which may be a problem.  The documentation for
3DSTATE_DEPTH_BUFFER mentions that depth stall flushes are required
before changing any depth/stencil buffer state, but explicitly lists
3DSTATE_DEPTH_BUFFER, 3DSTATE_HIER_DEPTH_BUFFER, 3DSTATE_STENCIL_BUFFER,
and 3DSTATE_CLEAR_PARAMS.  It does not mention this particular packet
(_3DSTATE_DEPTH_STENCIL_STATE_POINTERS).

No observed Piglit regressions on Sandybridge or Ivybridge.

Together with the last two commits, this makes a cairo-gl benchmark
faster by 0.324552% +/- 0.258355% on Ivybridge.  No statistically
significant change on Sandybridge.  (Thanks to Eric for the numbers.)

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