mlxsw: spectrum_router: Take VID for VLAN FIDs from RIF params

Currently, when an IP address is added to a bridge that has no PVID, the
operation is rejected. An IP address addition is interpreted as a request
to create a RIF for the bridge device, but without a PVID there is no VLAN
for which the RIF should be created. Thus the correct way to create a RIF
for a bridge as a user is to first add a PVID, and then add the IP address.

Ideally this ordering requirement would not exist. RIF would be created
either because an IP address is added, or because a PVID is added,
depending on which comes last.

For that, the switchdev code (which notices the PVID change request) must
be able to request that a RIF is created with a given VLAN ID, because at
the time that the PVID notification is distributed, the PVID setting is not
yet visible for querying.

Therefore when creating a VLAN-based RIF, use mlxsw_sp_rif_params.vid to
communicate the VID, and do not determine it ad-hoc in the fid_get
callback.

Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Danielle Ratson <danieller@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>