Set st_nlink in the stat structure within the inode to 1 as well.
The cd9660 file system uses that field for the link count and it
was 0. This impacts pwd_mkdb(8) as it checks for st_nlink not being
0 as part of closing a race.
Begin tidying up the reassociation and node sleep/wakeup paths.

* Move the node sleep/wake state under the TX lock rather than the
  node lock.  Let's leave the node lock protecting rate control only
  for now.

* When reassociating, various state needs to be cleared.  For example,
  the aggregate session needs to be torn down, including any pending
  aggregation negotiation and BAR TX waiting.

* .. and we need to do a "cleanup" pass since frames in the hardware
  TX queue need to be transmitted.

Modify ath_tx_tid_cleanup() to be called with the TX lock held and push
frames into a completion list.  This allows for the cleanup to be
done atomically for all TIDs in a node rather than grabbing and
releasing the TX lock each time.
This lock only protects the rate control state for now, mention this.
Oops, commit the other half of r250606.
Since the node state is 100% back under the TX lock, just kill the use
of atomics.

I'll re-think this nonsense later.