Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Add bluetooth fixes to the AR5416/AR92xx HAL:

* Call the bluetooth setup function during the reset path, so the bluetooth
settings are actually initialised.
* Call the AR9285 diversity functions during bluetooth setup; so the AR9285
diversity and antenna configuration registers are correctly programmed
* Misc debugging info.

Tested:

* AR9285+AR3011 bluetooth combo; this code itself doesn't enable bluetooth
coexistence but it's part of what I'm currently using.

Use the correct antenna configuration variable here. "diversity" just
controls whether it's on or off.

Found by: clang

Reformat/reindent.

Bring over the initial 802.11n bluetooth coexistence support code.

The Linux ath9k btcoex code is based off of this code.

Note this doesn't actually implement functional btcoex; there's some
driver glue and a whole lot of verification that is required.

On the other hand, I do have the AR9285+BT and AR9287+BT NICs which
this code supports..

Obtained from: Qualcomm Atheros, Linux ath9k