mlxsw: spectrum_router: Ignore IPv6 multipath notifications

IPv6 multipath notifications are about to be sent, but mlxsw is not
ready to process them, so ignore them.

The limitation will be lifted by a subsequent patch which will also stop
the kernel from sending a notification for each nexthop.
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

@@ -6203,6 +6203,8 @@ static int mlxsw_sp_router_fib_event(struct notifier_block *nb,
 				NL_SET_ERR_MSG_MOD(info->extack, "IPv6 route with nexthop objects is not supported");
 				return notifier_from_errno(-EINVAL);
 			}
+			if (fen6_info->multipath_rt)
+				return NOTIFY_DONE;
 		}
 		break;
 	}