ARM: at91: sama5d3/dt: add sama5d36ek dts files

Add .dts and .dtsi file to support sama5d36ek board.
Also update the the comments for sama5d36 in sama5d3.dtsi.

Signed-off-by: Josh Wu <josh.wu@atmel.com>
Acked-by: Boris BREZILLON <b.brezillon@overkiz.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Kevin Hilman <khilman@linaro.org>