intel/compiler: Silence unused parameter warning in compile_cs_to_nir

intel/compiler: Silence unused parameter warning in compile_cs_to_nir

src/intel/compiler/brw_fs.cpp: In function ‘nir_shader* compile_cs_to_nir(const brw_compiler*, void*, const brw_cs_prog_key*, brw_cs_prog_data*, const nir_shader*, unsigned int)’:
src/intel/compiler/brw_fs.cpp:7205:44: warning: unused parameter ‘prog_data’ [-Wunused-parameter]
                   struct brw_cs_prog_data *prog_data,
                                            ^~~~~~~~~

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>