Bluetooth: hci_conn: Fix not restoring ISO buffer count on disconnect

When disconnecting an ISO link the controller may not generate
HCI_EV_NUM_COMP_PKTS for unacked packets which needs to be restored in
hci_conn_del otherwise the host would assume they are still in use and
would not be able to use all the buffers available.

Fixes: 26afbd8 ("Bluetooth: Add initial implementation of CIS connections")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Tested-by: Frédéric Danis <frederic.danis@collabora.com>

net/bluetooth/hci_conn.c

@@ -1067,10 +1067,21 @@ int hci_conn_del(struct hci_conn *conn)
 			hdev->acl_cnt += conn->sent;
 	} else {
 		struct hci_conn *acl = conn->link;
+
 		if (acl) {
 			acl->link = NULL;
 			hci_conn_drop(acl);
 		}
+
+		/* Unacked ISO frames */
+		if (conn->type == ISO_LINK) {
+			if (hdev->iso_pkts)
+				hdev->iso_cnt += conn->sent;
+			else if (hdev->le_pkts)
+				hdev->le_cnt += conn->sent;
+			else
+				hdev->acl_cnt += conn->sent;
+		}
 	}
 
 	if (conn->amp_mgr)