net/mlx5: remove unused calculation in RSS expansion

net/mlx5: remove unused calculation in RSS expansion

The RSS flow expansion get a memory buffer to fill the new patterns of
the expanded flows.
This memory management saves the next address to write into the buffer
in a dedicated variable.

The calculation for the next address was wrongly also done when all the
patterns were ready.

Remove it.

Fixes: 4ed05fcd441b ("ethdev: add flow API to expand RSS flows")
Cc: stable@dpdk.org
Signed-off-by: Michael Baum <michaelba@nvidia.com>
Acked-by: Matan Azrad <matan@nvidia.com>