net/mlx5e: CT: Use per flow counter when CT flow accounting is enabled

Connection counters may be shared for both directions when the counter
is used for connection aging purposes. However, if TC flow
accounting is enabled then a unique counter is required per direction.

Instantiate a unique counter per direction if the conntrack accounting
extension is enabled. Use a shared counter when the connection accounting
extension is disabled.

Fixes: 1edae233

 ("net/mlx5e: CT: Use the same counter for both directions")
Signed-off-by: Oz Shlomo <ozsh@nvidia.com>
Reported-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Reviewed-by: Roi Dayan <roid@nvidia.com>
Reviewed-by: Paul Blakey <paulb@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>