Revert r330897:

This was intended to be a non-functional change. It wasn't. The commit
message was thus wrong. In addition it broke arm, and merged crypto
related code.

Revert with prejudice.

This revert skips files touched in r316370 since that commit was since
MFCed. This revert also skips files that require $FreeBSD$ property
changes.

Thank you to those who helped me get out of this mess including but not
limited to gonzo, kevans, rgrimes.

Requested by: gjb (re)

Partial merge of the SPDX changes

These changes are incomplete but are making it difficult
to determine what other changes can/should be merged.

No objections from: pfg

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

Migrate the LNA mixing diversity machinery from the AR9285 HAL to the driver.

The AR9485 chip and AR933x SoC both implement LNA diversity.
There are a few extra things that need to happen before this can be
flipped on for those chips (mostly to do with setting up the different
bias values and LNA1/LNA2 RSSI differences) but the first stage is
putting this code into the driver layer so it can be reused.

This has the added benefit of making it easier to expose configuration
options and diagnostic information via the ioctl API. That's not yet
being done but it sure would be nice to do so.

Tested:

* AR9285, with LNA diversity enabled
* AR9285, with LNA diversity disabled in EEPROM

Remove the AR9285 specific structure for LNA diversity and use the HAL.

The AR9300 HAL update included the LNA diversity configuration information
so it can be used in the AR9485 configuration code.

Migrate the AR9285 diversity configuration LNA configuration to use
some HAL definitions rather than local definitions.

The original source (ath9k) pulled this stuff from the QCA driver and
removed the HAL_* prefix. I'm just restoring the correct order of things.

Obtained from: Qualcomm Atheros

Some diversity changes relating to AR9285.

* grab the main, alt and selected LNA config
* add some optional / disabled logging code
* add a check to reject packets with an invalid main rssi too,
in case the alt is the active receive chain and main is -ve.

Note: The software-controlled combined diversity code is still disabled.

Import some initial Kite fixed diversity code from Atheros.

For now, the diversity settings are controlled by 'txantenna',
-not- rxantenna. This is because the earlier chipsets had
controllable TX diversity; the RX antenna setting twiddles
the default antenna register. I'll try sort that stuff out at
some point.

Call the antenna switch function from the board setup function
so scans, channel changes, mode changes, etc don't set the
diversity back to a default state too far from what's intended.

Things to todo:

* Squirrel away the last antenna diversity/combining parameters
and restore them during board setup if HAL_ANT_VARIABLE is
defined. That way scans, etc don't reset the diversity settings.

* Add some more public facing statistics, rather than what's
simply logged under HAL_DEBUG_DIVERSITY.

For now, the fixed antenna settings behave better than variable
settings for me. I have some further fiddling to do..

Obtained from: Atheros

More kite diversity related changes.

* add a diversity flag to the HAL debugging section
* add a check to make sure the kite diversity code doesn't run
on boards that don't require it, as not all Kite chips will
implement it.
* add some debug statements when the diversity code makes
changes to the antenna diversity/combining setup.

Bring over the antenna diversity logic support for Kite.

Again, this is just the code ported from ath9k and included in the build,
it isn't yet enabled.