net/mlx5: Update vport caps query/set for EC VFs

These functions are for query/set by vport, there was an underlying
assumption that vport was equal to function ID. That's not the case for
EC VF functions. Set the ec_vf_function bit accordingly.

Signed-off-by: Daniel Jurgens <danielj@nvidia.com>
Reviewed-by: William Tu <witu@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>