Bluetooth: Select Basic Mode as default for SOCK_SEQPACKET

The default mode for SOCK_SEQPACKET is Basic Mode. So when no
mode has been specified, Basic Mode shall be used.

This is important for current application to keep working as
expected and not cause a regression.
Signed-off-by: Gustavo F. Padovan <gustavo@las.ic.unicamp.br>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

net/bluetooth/l2cap.c

@@ -2205,7 +2205,7 @@ static int l2cap_build_conf_req(struct sock *sk, void *data)
 {
 	struct l2cap_pinfo *pi = l2cap_pi(sk);
 	struct l2cap_conf_req *req = data;
-	struct l2cap_conf_rfc rfc = { .mode = L2CAP_MODE_ERTM };
+	struct l2cap_conf_rfc rfc = { .mode = L2CAP_MODE_BASIC };
 	void *ptr = req->data;
 
 	BT_DBG("sk %p", sk);