i965: Update 3DSTATE_{DEPTH,STENCIL,...}_BUFFER and such for Broadwell.

i965: Update 3DSTATE_{DEPTH,STENCIL,...}_BUFFER and such for Broadwell.

The amount of cut and paste from Gen7 is rather ugly, and should
probably be cleaned up in the future.  Even the Gen7 code is in need of
some tidying though; many of the function parameters aren't used on
platforms that use level/layer rather than tile offsets.  Tidying both
can be left to a future patch series.  This at least gets things going.

v2: Rebase on Paul's rename of NumLayers -> MaxNumLayers.

v3: Shift QPitch by 2 when storing it in the packet.  Bits 14:0 store
    bits 16:2 of the actual value.  Fixes tests.

v4: Add missing stencil buffer QPitch.

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Acked-by: Eric Anholt <eric@anholt.net>