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 num_med_bfreg(struct mlx5_ib_dev *dev,
			 struct mlx5_bfreg_info *bfregi)
{
	int n;

	n = max_bfregs(dev, bfregi) - bfregi->num_low_latency_bfregs -
	    NUM_NON_BLUE_FLAME_BFREGS;

	return n >= 0 ? n : 0;
}

static int num_med_bfreg(struct mlx5_ib_dev *dev,
			 struct mlx5_bfreg_info *bfregi)
{
	int n;

	n = max_bfregs(dev, bfregi) - bfregi->num_low_latency_bfregs -
	    NUM_NON_BLUE_FLAME_BFREGS;

	return n >= 0 ? n : 0;
}
