[net80211] PR kern/166286: force a channel change upon a HT info change

[Adrian Chadd]

Hi,

Here's a second patch. This patch:

* Implements a channel width change taskqueue event;
* Queues this event whenever a channel width change occurs from beacon frames;
* Added a simple change to if_ath to call ath_chan_set() upon receipt
of a channel width notification.

TODO:

* Move the chw routines from ieee80211_node.c/ieee80211_proto.c into
ieee80211_ht.c;
* Test it with CSAs to ensure we don't get multiple channel changes
that aren't necessary.

This seems simpler than adding a new state. But, hm, I can't help but
wonder whether the correct thing to do here is add a new state that
transitions ASSOC -> CHW -> ASSOC.

Also there may be other htinfo changes - eg, if an AP decides to
change from enabling to disabling RIFS. That currently isn't handled.


Adrian