net/mlx5: Remove no longer used mlx5_esw_offloads_sf_vport_enable/disable()

Since the previous patch removed the only users of these functions,
remove them.

Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Reviewed-by: Shay Drory <shayd@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>