net/mlx5e: CT, optimize pre_ct table lookup

The pre_ct table realizes in hardware the act_ct cache logic, bypassing
the CT table if the ct state was already set by a previous ct lookup.
As such, the pre_ct table will always miss for chain 0 filters.

Optimize the pre_ct table lookup for rules installed on chain 0.

Signed-off-by: Oz Shlomo <ozsh@nvidia.com>
Reviewed-by: Roi Dayan <roid@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>