Bluetooth: Fix a compile warning in RFCOMM

sock and sk were leftover from another change.
Signed-off-by: NGustavo F. Padovan <padovan@profusion.mobi>

net/bluetooth/rfcomm/core.c

@@ -1774,9 +1774,6 @@ static inline int rfcomm_process_tx(struct rfcomm_dlc *d)
 		return skb_queue_len(&d->tx_queue);
 
 	while (d->tx_credits && (skb = skb_dequeue(&d->tx_queue))) {
-		struct socket *sock = d->session->sock;
-		struct sock *sk = sock->sk;
-
 		err = rfcomm_send_frame(d->session, skb->data, skb->len);
 		if (err < 0) {
 			skb_queue_head(&d->tx_queue, skb);