firewire net: Allocate address handler before registering net_device.

Allocate FIFO address before registering net_device.
This is preparation to change the pseudo hardware address format
for firewire devices to include the offset of the FIFO for receipt
of unicast datagrams, instead of mangling ARP/NDP messages in the
driver layer.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>