Southern Islands gallium support

[Alex Deucher]

I've gone ahead and pushed the initial SI gallium driver to my mesa
tree on fdo.  The new driver is called radeonsi.  I've left it in my
personal repo for now as Tom wants to restructure the llvm stuff
before we merged it into mesa proper.  You can find the code here
(http://cgit.freedesktop.org/~agd5f/mesa) on the radeonsi branch once
cgit picks up the new repo.

Basic egl demos are starting to run.  There is no ddx for SI right
now.  The plan is to support X acceleration via gallium.

The shader ISA documentation is also getting finished up and should be out soon.

git://people.freedesktop.org/~agd5f/mesa
ssh://people.freedesktop.org/~agd5f/mesa

Alex