Merge changes Id0a22412,I4a18d89e,I8b70fb37,I3d030824

* changes:
  enum-ify stack/include/btm_api_types::BTM_SEC_MODE_
  Re-log stack/l2cap/l2c_api::L2CA_SendFixedChnlData
  Re-log stack/gatt/gatt_cl::gatt_act_discovery
  Re-log stack/gatt/att_protocol::attp_send_msg_to_l2cap