Add support for zero queue sizes of the traffic classes. The queues which are not used can be set to zero size. This helps in reducing memory footprint of the hierarchical scheduler. Signed-off-by: Jasvinder Singh <jasvinder.singh@intel.com> Signed-off-by: Abraham Tovar <abrahamx.tovar@intel.com> Signed-off-by: Lukasz Krakowiak <lukaszx.krakowiak@intel.com>