mlxsw: spectrum_router: Do not configure VID for sub-port RIFs

The field 'vid' in RITR is reserved when unified bridge model is used
and the RIF's type is sub-port RIF. Instead, ingress VID is configured via
SVFA and egress VID is configured via REIV.

Set 'vid' to zero in RITR register for sub-port RIF when unified bridge
model is used.

Signed-off-by: Amit Cohen <amcohen@nvidia.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>