Track the state of streamon/streamoff calls to simplify error paths. Ensuring that streamOff() can be called on non-streaming streams facilitates simpler error code paths, where a set of devices can all call streamOff regardless of their initialisation state. Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com> Signed-off-by: Umang Jain <email@uajain.com> Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>