IB/mlx5: Fix leaking stack memory to userspace

mlx5_ib_create_qp_resp was never initialized and only the first 4 bytes
were written.

Fixes: 41d902cb7c32 ("RDMA/mlx5: Fix definition of mlx5_ib_create_qp_resp")
Cc: <stable@vger.kernel.org>
Acked-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
static int begin_wqe(struct mlx5_ib_qp *qp, void **seg,
		     struct mlx5_wqe_ctrl_seg **ctrl,
		     const struct ib_send_wr *wr, unsigned *idx,
		     int *size, int nreq)
{
	return __begin_wqe(qp, seg, ctrl, wr, idx, size, nreq,
			   wr->send_flags & IB_SEND_SIGNALED,
			   wr->send_flags & IB_SEND_SOLICITED);
}

static int begin_wqe(struct mlx5_ib_qp *qp, void **seg,
		     struct mlx5_wqe_ctrl_seg **ctrl,
		     const struct ib_send_wr *wr, unsigned *idx,
		     int *size, int nreq)
{
	return __begin_wqe(qp, seg, ctrl, wr, idx, size, nreq,
			   wr->send_flags & IB_SEND_SIGNALED,
			   wr->send_flags & IB_SEND_SOLICITED);
}
