at91: Introduction of at91sam9g45 SOC.

AT91sam9g45 series is an ARM 926ej-s SOC family clocked at 400/133MHz.
It embeds USB high speed host and device, LCD, DDR2 RAM, and a full set of
peripherals.

The first board that embeds at91sam9g45 chip is the AT91SAM9G45-EKES.
On the board you can find 2 USART, USB high speed,
a 480*272 LG lcd, ethernet, gpio/joystick/buttons.

Signed-off-by: Sedji Gaouaou <sedji.gaouaou@atmel.com>