at91: Support for the at91sam9g20 : Atmel 400Mhz ARM 926ej-s SOC.

AT91sam9g20 is an evolution of the at91sam9260 with a faster clock speed.

The AT91SAM9G20-EK board is an updated revision of the AT91SAM9260-EK board.
It is essentially the same, with a few minor differences.

Here is the chip page on Atmel website:
http://www.atmel.com/dyn/products/product_card.asp?part_id=4337



Signed-off-by: Justin Waters <justin.waters@timesys.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>