net/mlx5: remove unused reference counter

net/mlx5: remove unused reference counter

In the previous implementation, a count was used to record the number
of the references to a table resource, including the creation of the
table, the jumping to the table and the matchers created on the
table. Before releasing the table resource via the driver, it needed
to ensure that there is no reference to this table.

After the optimization of the resources management, the reference
count now is in the hash list entry as a unified solution for all the
resources management.

There is no need to keep the "refcnt" in the table resource
structure. It is removed in case that there is some unnecessary
memory overhead.

Fixes: afd7a62514ad ("net/mlx5: make flow table cache thread safe")
Cc: stable@dpdk.org
Signed-off-by: Bing Zhao <bingz@nvidia.com>
Acked-by: Matan Azrad <matan@nvidia.com>