r600: drop a bunch of post-cayman code. (v2)

r600: drop a bunch of post-cayman code. (v2)

Now that Marek has split the two drivers apart, drop a bunch
of unnecessary code from the r600 half. There is probably a bunch
more hiding in the video code.

No piglit regressions on caicos.

v2: fix HAVE_LLVM protected code
Acked-by: Nicolai Hähnle <nicolai.haehnle@amd.com>
Acked-by: Marek Olšák <marek.olsak@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>