Previously the main pfsync lock and the bucket locks shared the same name.
This lead to spurious warnings from WITNESS like this:
acquiring duplicate lock of same type: "pfsync"
1st pfsync @ /usr/src/sys/netpfil/pf/if_pfsync.c:1402
2nd pfsync @ /usr/src/sys/netpfil/pf/if_pfsync.c:1429
It's perfectly okay to grab both the main pfsync lock and a bucket lock at the
same time.
We don't need different names for each bucket lock, because we should always
only acquire a single one of those at a time.
MFC after: 1 week