net/mlx5: Remove pointless vport lookup from mlx5_esw_check_port_type()

As xa_get_mark() returns false in case the entry is not present,
no need to redundantly check if vport is present. Remove the lookup.

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