Fast-frames:
* include opt_wlan.h ; tsk to not doing it earlier;
* add a tx pending tracking counter for seeing how deep
the hardware TX queue is;
* add the frame aging code from if_ath;
* add fast-frames capability to the driver setup.
Bugs:
* free the buffers (and node references) before
detaching net80211 state. This prevents a use-after-free in
the node free path where we've destroyed net80211 underneath it.
Atheros.
Thanks to OpenBSD for providing a driver based on the original
Atheros open source driver circa 2008. This uses the early, pre-carl9170
atheros provided firmware.
It only supports 11bg at the moment. I've not tested it with 11a
(and so the TX rate control logic may be slightly wrong!) so if
you do have the dual-band version of this hardware please do let me know.
Tested:
* AR9170, TP-Link WN821N 2GHz.
TODO:
* Hook this up to a non-module build.
