net: dsa: Copy the routing table into the switch structure

The new binding will not have a chip data structure, it will place the
routing directly into the switch structure. To enable backwards
compatibility, copy the routing from the chip data into the switch
structure.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: David S. Miller <davem@davemloft.net>