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)

Preparation work for supporting the AR91xx and AR724x.

* Implement a SoC probe function, from Linux, which determines the
SoC family, type and revision. This only probes the AR71xx series
SoC and (currently) panics on others.

* Migrate some of the AR71XX specific hardware init (USB device, determining
system frequencies) into using the cpuops introduced in an earlier commit.
Other SoC specific hardware stuff (per-device flush/WB, GPIO pin wiring,
Ethernet PLL setup, other things I've likely missed) will be introduced in
subsequent commits.

Reviewed by: imp@
Obtained from: (partially) Linux

Extend the AR71XX watchdog debugging and data.

* Add some per-device sysctl entries which record the watchdog state -
whether it is armed; whether the last reboot was due to the watchdog.
* Add a per-device sysctl debug flag to enable logging watchdog arming/
disarming.

Reviewed by: gonzo@

Set the svn:eol-style = native and svn:mime-type = text/plain
properties on all files in this tree.

Submitted by: rpaulo@

Place proper svn:keywords tag on all these files. They were created
somehow without them on projects/mips, and that mistake was propigated
over to head.

Submitted by: rpaulo@

Merge from projects/mips to head by hand:

Merge support files for the Atheros AR71xx (and soon AR9xxx)
processors, except files from sys/conf and sys/mips/conf. This work
was done primarily by Olecksandr Tymoshenko and works on the
RouterStation and RouterStation PRO. Other AR71xx-based boards have
been reported as working as well (RouterBoard, for example).

- Add AR71XX watchdog timer driver