[U-Boot] AT91: working port for Atmels AT91SAM9XE-EK (should be good for )G20 and 9260, too)

[Reinhard Meyer]

In line with the at91/avr32 rework efforts, I have made the board
AT91SAM9XE-EK build and work again.

Note however that I could not test all functions of the board thoroughly.
MMC with the generic driver is working, note that dataflash and mmc are
mutually exclusive on those evaluation boards.

If you want to try the build, you can find it at top of the rework tree
in u-boot-atmel.git, at91avr32rework-5 branch.

Note also that you need the initial bootstrap loader recompiled to load
the image to 0x20000000, OR (not recommended) change the
CONFIG_SYS_TEXTBASE back to 0x23f00000 which is 1 Meg. below end of SDRAM
and therefore a bit close to the relocated u-boot image.

Reinhard