IB/mlx4: Simplify retrieval of ib_device

struct ib_qp  already holds a pointer to the ib device. No need to dive to the
hw device object to retrieve it.
Signed-off-by: NEli Cohen <eli@mellanox.co.il>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

drivers/infiniband/hw/mlx4/qp.c

@@ -1214,7 +1214,7 @@ out:
 static int build_mlx_header(struct mlx4_ib_sqp *sqp, struct ib_send_wr *wr,
 			    void *wqe, unsigned *mlx_seg_len)
 {
-	struct ib_device *ib_dev = &to_mdev(sqp->qp.ibqp.device)->ib_dev;
+	struct ib_device *ib_dev = sqp->qp.ibqp.device;
 	struct mlx4_wqe_mlx_seg *mlx = wqe;
 	struct mlx4_wqe_inline_seg *inl = wqe + sizeof *mlx;
 	struct mlx4_ib_ah *ah = to_mah(wr->wr.ud.ah);