anv: use the common function for detecting a mesh shader stage

Signed-off-by: Rohan Garg <rohan.garg@intel.com>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/34604>

src/intel/vulkan/anv_pipeline.c

@@ -978,8 +978,7 @@ anv_pipeline_lower_nir(struct anv_pipeline *pipeline,
                });
    }
 
-   if (nir->info.stage == MESA_SHADER_MESH ||
-         nir->info.stage == MESA_SHADER_TASK) {
+   if (gl_shader_stage_is_mesh(nir->info.stage)) {
       nir_lower_compute_system_values_options options = {
             .lower_workgroup_id_to_index = true,
             /* nir_lower_idiv generates expensive code */