firewire: net: fix card driver reloading
Fix some problems from "firewire: net: allow for unordered unit
discovery":
- fwnet_remove was missing a list_del, causing fwnet_probe to crash if
called after fwnet_remove, e.g. if firewire-ohci was unloaded and
reloaded.
- fwnet_probe should set its new_netdev flag only if it actually
allocated a net_device.
- Use dev_set_drvdata and dev_get_drvdata instead of deprecated direct
access to device.driver_data.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>