net/mlx5e: TC, Move main flow attribute cleanup to helper func

Actions that can be setup per flow attribute (so per split rule)
are cleaned up from mlx5_free_flow_attr(), mlx5e_tc_del_fdb_flow(),
and free_flow_post_acts().

Remove the duplication by re-using the helper function for
the main flow attribute and split rules attributes.

Signed-off-by: Paul Blakey <paulb@nvidia.com>
Reviewed-by: Roi Dayan <roid@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>