RootCanal: Remove unused members in LinkLayerController

 private:

  const DeviceProperties& properties_;

  AclConnectionHandler connections_;

  // Add timestamps?

  std::vector<std::shared_ptr<model::packets::LinkLayerPacketBuilder>>

      commands_awaiting_responses_;

  // Timing related state

  std::vector<AsyncTaskId> controller_events_;

  std::chrono::milliseconds timer_period_ = std::chrono::milliseconds(100);

  // Callbacks to schedule tasks.

  std::function<AsyncTaskId(std::chrono::milliseconds, const TaskCallback&)>

  uint32_t key_id_ = 1;

  // LE state

  std::vector<uint8_t> le_event_mask_;

  std::vector<std::tuple<Address, uint8_t>> le_connect_list_;

  struct ResolvingListEntry {

    Address address;