firewire: prefix modules with firewire- instead of fw-

Of course everybody immediately associates "fw-" with FireWire, not
firmware or firewall or whatever.  But "firewire-" has a nice ring to
it too.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Acked-by: Kristian Hoegsberg <krh@bitplanet.net>