net/mlx5: Lag, set different uplink vport metadata in multiport eswitch mode

In a follow-up commit multiport eswitch mode will use a shared fdb.
In shared fdb there is a single eswitch fdb and traffic could come from any
port. to distinguish between the ports set a different metadata per uplink port.

Signed-off-by: Roi Dayan <roid@nvidia.com>
Reviewed-by: Maor Dickman <maord@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>