mlxsw: spectrum_router: Remove RTNL assertion

Remove the RTNL assertion in the nexthop notifier block. The assertion
is not needed given RTNL is never assumed to be taken.

This is a preparation for future patches where mlxsw will start handling
nexthop events that are not always sent with RTNL held.
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c

@@ -4699,8 +4699,6 @@ static int mlxsw_sp_nexthop_obj_event(struct notifier_block *nb,
 
 	mutex_lock(&router->lock);
 
-	ASSERT_RTNL();
-
 	switch (event) {
 	case NEXTHOP_EVENT_REPLACE:
 		err = mlxsw_sp_nexthop_obj_new(router->mlxsw_sp, info);