firewire: net: use dev_printk API

Change the log line prefix from "firewire_net: " to "net firewire0: "
etc. for the case that several RFC 2734 interfaces are being used in the
same machine.

Note, the netdev_printk API is not very useful to firewire-net.
netdev_notice(net, "abc\n") would result in irritating messages like
"firewire_ohci 0000:0a:00.0: firewire0: abc".  Nor would a dev_printk on
the fw_unit.device to which firewire-net is being bound be useful,
because there are generally multiple ones of those per interface (from
all RFC 2734 peers on the bus, the local node being only one of them).

In the initialization message of each interface, log the PCI device
name of the card which is parent of the netdevice instead of the GUID
of the peer which was semi-randomly used to establish the netdevice.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>