The PipelineHandlerFactory::registerType() function is called by the PipelineHandlerFactory class only. Make it private. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Xavier Roumegue <xavier.roumegue@oss.nxp.com> Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>