Because of a typo, mlx4_ib_post_send() takes the same lock rq.lock as
mlx4_ib_post_recv().  Correct the code so the intended sq.lock is
taken when posting a send.
Noticed by Yossi Leybovitch and pointed out by Jack Morgenstein from
Mellanox.
Signed-off-by: Roland Dreier <rolandd@cisco.com>
        int size;
        int i;
 
-       spin_lock_irqsave(&qp->rq.lock, flags);
+       spin_lock_irqsave(&qp->sq.lock, flags);
 
        ind = qp->sq.head;
 
                               (qp->sq.wqe_cnt - 1));
        }
 
-       spin_unlock_irqrestore(&qp->rq.lock, flags);
+       spin_unlock_irqrestore(&qp->sq.lock, flags);
 
        return err;
 }