Bluetooth: Send Ack after clear the SREJ list

As specified by Bluetooth 3.0 spec we shall send an acknowledgment using
the Send-Ack() after clear the SREJ list.
Signed-off-by: NGustavo F. Padovan <padovan@profusion.mobi>
Reviewed-by: NJoão Paulo Rechi Vita <jprvita@profusion.mobi>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

net/bluetooth/l2cap.c

@@ -3493,6 +3493,7 @@ static inline int l2cap_data_channel_iframe(struct sock *sk, u16 rx_control, str
 			if (list_empty(SREJ_LIST(sk))) {
 				pi->buffer_seq = pi->buffer_seq_srej;
 				pi->conn_state &= ~L2CAP_CONN_SREJ_SENT;
+				l2cap_send_ack(pi);
 			}
 		} else {
 			struct srej_list *l;