[Mesa-dev] Reducing update_texture_state overhead

[Eric Anholt]

Here's an attempt at cutting update_texture_state overhead, which has
been noted a few times as a big CPU consumer in Mesa.  It looks pretty
promising on gen7 (though the binding table patches in the other
series would make the impact of patch 2 less significant).  However,
with the GPU hangs in the second patch, I'm wondering whether I'm
missing some reason that _NEW_TEXTURE would need to be flagged in this
function.