ARM: at91: dt: Add at91sam9261 dt SoC support

This patch adds support for the Device Tree on a sam9261-based platform

Signed-off-by: Jean-Jacques Hiblot <jjhiblot@traphandler.com>
Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>