intel/brw: Rely on existing helper for dispatch width of geometry stages

Helper already exists and is used in the functions, just save the value
so can be reused.

Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/33175>

src/intel/compiler/brw_compile_tcs.cpp

@@ -192,6 +192,7 @@ brw_compile_tcs(const struct brw_compiler *compiler,
    const struct brw_tcs_prog_key *key = params->key;
    struct brw_tcs_prog_data *prog_data = params->prog_data;
    struct brw_vue_prog_data *vue_prog_data = &prog_data->base;
+   const unsigned dispatch_width = brw_geometry_stage_dispatch_width(compiler->devinfo);
 
    const bool debug_enabled = brw_should_print_shader(nir, DEBUG_TCS);
 
@@ -209,8 +210,7 @@ brw_compile_tcs(const struct brw_compiler *compiler,
                             nir->info.outputs_written,
                             nir->info.patch_outputs_written);
 
-   brw_nir_apply_key(nir, compiler, &key->base,
-                     brw_geometry_stage_dispatch_width(compiler->devinfo));
+   brw_nir_apply_key(nir, compiler, &key->base, dispatch_width);
    brw_nir_lower_vue_inputs(nir, &input_vue_map);
    brw_nir_lower_tcs_outputs(nir, &vue_prog_data->vue_map,
                              key->_tes_primitive_mode);
@@ -276,7 +276,6 @@ brw_compile_tcs(const struct brw_compiler *compiler,
       brw_print_vue_map(stderr, &vue_prog_data->vue_map, MESA_SHADER_TESS_CTRL);
    }
 
-   const unsigned dispatch_width = devinfo->ver >= 20 ? 16 : 8;
    fs_visitor v(compiler, &params->base, &key->base,
                 &prog_data->base.base, nir, dispatch_width,
                 params->base.stats != NULL, debug_enabled);