mlxsw: spectrum_switchdev: Prepare for locked FDB notifications

Subsequent patches will need to report locked FDB entries to the bridge
driver. Prepare for that by adding a 'locked' argument to
mlxsw_sp_fdb_call_notifiers() according to which the 'locked' bit is set
in the FDB notification info. For now, always pass 'false'.

Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>