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

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

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

Approved by: re (implicit)

Introduce AR9130 (HOWL) WMAC support to the FreeBSD HAL.

The AR9130 is an AR9160/AR5416 family WMAC which is glued directly
to the AR913x SoC peripheral bus (APB) rather than via a PCI/PCIe
bridge.

The specifics:

* A new build option is required to use the AR9130 - AH_SUPPORT_AR9130.
This is needed due to the different location the RTC registers live
with this chip; hopefully this will be undone in the future.
This does currently mean that enabling this option will break non-AR9130
builds, so don't enable it unless you're specifically building an image
for the AR913x SoC.

* Add the new probe, attach, EEPROM and PLL methods specific to Howl.

* Add a work-around to ah_eeprom_v14.c which disables some of the checks
for endian-ness and magic in the EEPROM image if an eepromdata block
is provided. This'll be fixed at a later stage by porting the ath9k
probe code and making sure it doesn't break in other setups (which
my previous attempt at this did.)

* Sprinkle Howl modifications throughput the interrupt path - it doesn't
implement the SYNC interrupt registers, so ignore those.

* Sprinkle Howl chip powerup/down throughout the reset path; the RTC methods
were

* Sprinkle some other Howl workarounds in the reset path.

* Hard-code an alternative setup for the AR_CFG register for Howl, that
sets up things suitable for Big-Endian MIPS (which is the only platform
this chip is glued to.)

This has been tested on the AR913x based TP-Link WR-1043nd mode, in
legacy, HT/20 and HT/40 modes.

Caveats:

* 2ghz has only been tested. I've not seen any 5ghz radios glued to this
chipset so I can't test it.

* AR5416_INTERRUPT_MITIGATION is not supported on the AR9130. At least,
it isn't implemented in ath9k. Please don't enable this.

* This hasn't been tested in MBSS mode or in RX/TX block-aggregation mode.