mlxsw: spectrum_router: Implement next-hop routing

Implement next-hop routing offload including ECMP. To make it possible,
introduce next-hop group entity. This entity keeps track of resolved
neighbours and updates HW adjacency table accordingly. Note that HW
next-hops are stored in this adjacency table, in form of MAC.
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlxsw/spectrum.h

@@ -222,6 +222,7 @@ struct mlxsw_sp_router {
 		struct delayed_work dw;
 		unsigned long interval;	/* ms */
 	} neighs_update;
+	struct list_head nexthop_group_list;
 };
 
 struct mlxsw_sp {