CFT: new ath hal

I've placed a new hal out for testing.  I'd like to commit it after more
folks work with it so feedback would be helpful.

http://people.freebsd.org/~sam/ath_hal-20061205.tgz

There are numerous small bugs fixed in this version but the main change
is a split of the descriptor state so that s/w state can be placed in
cached memory when h/w state is in uncached memory.  This results in
noticeable performance gains on certain architectures.

To use this hal you must patch the driver and rate control modules with
this:

http://people.freebsd.org/~sam/ath-20061205.patch

Not sure if the patch will apply cleanly to RELENG_6.

	Sam