[Mesa-dev] mesa/intel: format handling updates.

[Eric Anholt]

Two Mesa patches that might be generally interesting, then I proceed to
slowly update the texture formats mappings in i965.

One of the original goals was to remove the alpha-channel forcing code in
our sampler state, but I couldn't quite find enough supported formats to
do so.

The code can be found in the "formats" branch of my tree.  This patch
series won't actually apply, because of what I did for review's sake in
patch 2/11.