mesa: Rename MESA_shader_integer_mix to EXT_shader_integer_mix

Everyone at the Khronos meeting was as surprised that GLSL didn't
already support this as we were.  Several vendors said they'd ship it,
but there didn't seem to be enough interest to put in the effort to make
it ARB or KHR.

v2: Fix a couple typos and rename the spec file to
EXT_shader_integer_mix.spec.  Suggested by Roland.

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Matt Turner <mattst88@gmail.com>
Reviewed-by: Roland Scheidegger <sroland@vmware.com>
i965: Add comments to the new brw_state_state structure's fields.

These are largely based on the similar fields in brw->wm.

v2: Add a better comment than "Scratch buffer".

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Paul Berry <stereotype441@gmail.com>
i965: Increase the size of brw_stage_state::surf_offset.

Since BRW_MAX_WM_SURFACES is greater than BRW_MAX_VEC4_SURFACES, the
existing array isn't large enough to be used by the WM.  Increasing it
will make it possible to share them.

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Paul Berry <stereotype441@gmail.com>
i965: Use brw_stage_state for WM data as well.

This gets the VS, GS, and PS all using the same data structure.

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