Copy stable/10@r272459 to releng/10.1 as part of
the 10.1-RELEASE process.

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

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

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

Create a generic way to support multiple boards within an
arm platform. Add all the atmel boards to the ATMEL kernel for
testing purposes. Until boot loader arg parsing of baord type
is done, this won't actually be able to do the runtime selection.

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.

Import preliminary support for Atmel AT91SAM9G20 cpu, and the Hot-e HL201.
This fine work was done by Yohanes Nugroho <yohanes a gmail dot com>
Many thanks to John Nicholls and Thinlinx for providing sample hardware.