i965: Move compute shader code around

i965: Move compute shader code around

This moves the compute shader code around in order to make the way the
code is split up more consistent. There should be no functional changes.
Typically we have a few files per stage:

    brw_vs.c, brw_wm.c brw_gs.c:

        code to drive code generation and implement precompiling and
        cache search.

    genX_<stage>_state.c

        gen specific implementation of the state emission for the shader
        stage.

The brw_*_emit() functions are all in the same files as the visitor
classes they use (with the exception of VS, which may use either vec4 or
fs).

To make compute follow this convention, we move the brw_cs_emit()
function into brw_fs.cpp. We can then rename brw_cs.cpp to brw_cs.c and
do this in C like the other similar files.  Finally, move state setup
and atoms to gen7_cs_state.c.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
Signed-off-by: Kristian Høgsberg Kristensen <krh@bitplanet.net>