firewire: fix synchronization of gap counts

Fix:  The fact that nodes had different gap counts would be overlooked
if the bus manager code would pick gap count 63 because of beta
repeaters or because of very large hop counts.  In this case, the bus
manager code would miss that it actually has to send the PHY config
packet with gap count 63.

Related trivial changes:  Use bool for an int used as bool, touch up
some comments.

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