Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

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

MFC r243164 (by adrian):

I'm not sure why ah_desc.h was required here, but it doesn't _need_
to be. So, just toss it.

There's no options or ah_desc fields in here.

Whilst I'm here, fix up the #ifdef and #define to mach.

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

Add in descriptions for TX descriptor fields ctl8-11 - these fields
control the antenna control bits for the four TX series and the
TPC settings for TX series 1, 2, 3.

The specifics:

* The TPC setting for TX series 0 is handled in ctl0.

* TPC is currently disabled, so the per-packet TX power is
set via the global per-rate TX power register, not per packet.

* The antenna control bits don't matter for AR5416 and later
so they should stay 0 (which they currently do); they may
be set for Kite but as there's no TX diversity supported
at the moment (it requires the NIC to be built with an
external antenna switch, matching how antenna diversity
is done on legacy NICs), so again keep them 0.

This is in preparation for supporting per-rate TPC on the
AR5416 and later. The Kite (and soon to come Kiwi) code
sets ctl8-11 to 0x0, which doesn't have any effect at
the moment. When TPC is enabled it would result in the
second, third and fourth TX series attmpts to be done with
a TX power of 0. This commit doesn't change that; it'll
be followed up with some commits to properly set the TPC
registers appropriately.

Change AR_SREV_OWL_{X}_OR_LATER to AR_SREV_5416_{X}_OR_LATER.

For now, these are equivalent macros. AR_SREV_OWL{X}_OR_LATER
will later change to exclude Howl (AR9130) in line with what
the Atheros HAL does.

This should not functionally change anything.

Obtained from: Atheros

Replace Id keyword with the FreeBSD keyword.

add FreeBSD property

import ath hal

Update to later code from my repository:
o many bug fixes
o add new periodic calibration api
o break up 5416 periodic calibration code in preparation for 928x
o move get noise floor to rf backends
o 5416-specific ani (still disabled)
o modularize 5210 eeprom format a la other eeprom formats
o start cleaning up regdomain code
o prepare for proper 1/2 and 1/4 width channel support
o bring back 900MHz card support
o clean up 5212 rf version handling
o add 1/2 and 1/4 width channel support for 5212 parts
o split 5212 rfgain handling out
o improve ani debugging
o add AH_USE_INIPDGAIN compile option
o purge a bunch of dead 5212 state
o add 1/2 and 1/4 rate modes
o remove HAL_CAP_CHAN_HALFRATE and HAL_CAP_CHAN_QUARTERRATE; the
same info can now be deduced from the set of supported modes

virgin import of ath hal