hci_unit_lookup
struct hci_unit *hci_unit_lookup(const bdaddr_t *);
unit = hci_unit_lookup(&btr->btr_bdaddr);
if (hci_unit_lookup(&sa->bt_bdaddr) == NULL)
unit = hci_unit_lookup((sa ? &sa->bt_bdaddr : &pcb->hp_raddr));
unit = hci_unit_lookup(&chan->lc_laddr.bt_bdaddr);
unit = hci_unit_lookup(&pcb->sp_laddr);