Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

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

Add support for the Atmel SAM9XE familiy of microcontrollers, which
consist of a ARM926EJ-S processor core with up to 512 Kbytes of on-chip
flash. Tested with SAM9XE512.

- Try to bring these files closer to style(9).
- Use DEVMETHOD_END.
- Use NULL instead of 0 for pointers.

if_ate.c:

* Support for sam9 "EMAC" controller.
* Support for rmii interface to phy.

at91.c & at91sam9.c:

* Eliminate separate at91sam9.c file.
* Add new devices to at91sam9_devs table.

at91_machdep.c & at at91sam9_machdep.c:

* Automatic chip type determination.
* Remove compile time chip dependencies.
* Eliminate separate at91sam9_machdep.c file.

at91_pmc.c:

* Corrected support for all of the sam926? and sam9g20 chips.
* Remove compile time chip dependencies.

My apologies to Greg for taking so long to take care of it.

Use at91_master_clock instead of AT91C_MASTER_CLOCK.

Tweak the disclaimer section of the license to match COPYRIGHT, for
better or worse. Ok'd by folks that have additional copyrights to the
files in cases where there's joint authorship.

MFp4: A bunch of patches from myself and Tisco to improve the
robustness of IIC transactions when parts aren't present. This also
removes a bunch of debug. This also moves this driver to 7-1
addressing rather than 6-0 addressing, which is more inline with all
the other iic drivers in the tree. I've tested this for about a
million years on the systems at work.

Import support for the Atmel AT91RM9200 CPU/Microcontroller. This SoC
is a ARM920T based CPU with a bunch of built-in peripherals. The
inital import supports the SPI bus, the TWI bus (although iicbus
integration is not complete), the uarts, the system timer and the
onboard ethernet. Support for the Kwikbyte KB9202
(http://www.kwikbyte.com) board is also included, although there's no
reason why the 9200 and the 9201 wouldn't also work. Primitive
support for running under the skyeye emulator is also provided
(although skyeye's support for the AT91RM9200 is a little weak).

The code has been structured so that other members of Atmel's arm family can
be supported in the future. The AT91SAM9260 is not presently supported
due to lack of hardware. The arm7tdmi families are also not supported
becasue they lack an MMU.

Many thanks to cognet@ for his help and assistance in bringing up this
board. He did much of the vm work and wrote parts of the uart and
system timer code as well as the bus space implementation.

The system boots to single user w/o problem, although the serial
console is a little slow and the ethernet driver is still in flux.

This work was sponsored by Timing Solutions, Corporation. I am
grateful to their support of the FreeBSD project in this manner.