i965: Use a single binding table for all pipeline stages.

i965: Use a single binding table for all pipeline stages.

Although the hardware supports separate binding tables for each pipeline
stage, we don't see much advantage over a single shared table.

Consider the contents of the binding table:
- Textures (16)
- Draw buffers (8)
- Pull constant buffers (1 for VS, 1 for WM)

OpenGL's texture bindings are global: the same set of textures is
available to all shader targets.  So our binding table entries for
textures would be exactly the same in every table.

There are only two pull constant buffers (not many), and although draw
buffers aren't interesting to the VS, it shouldn't hurt to have them in
the table.  The hardware supports up to 254 binding table entries, and
we currently only use 26.

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Paul Berry <stereotype441@gmail.com>