Saturday night @ ucc: 11n hackery

I'm going to work on the FreeBSD 802.11n support a little more this upcoming Friday night and Saturday at UCC.

My short-short term TODO list:

1. Figure out why crypto isn't working in 11n mode - I've likely just not fully implemented something there;
2. Hopefully I'll have the AR9220 based SR-71 cards by then - so if I do, see whether my HAL works on the AR9280 and AR9220 based NICs;
3. Test the legacy HAL (AR5212 support at least) to make sure I haven't broken that;
4. Make the TX path run-time configurable rather than a compile #ifdef - ie, if the card says it does 11n, use the 11n-aware TX routines;
5. Keep breaking apart sys/dev/ath/if_ath.c into smaller parts to make this whole thing more manageable moving forward.
   

That's all I think I need to finish up before I begin preparation for committing this work to FreeBSD-HEAD.