ARM: dts: exynos: Enable SSS on Trats2

Enable the Security SubSystem (SSS) on Trats2 (Exynos4412) board to
provide hardware acceleration for AES operations.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Reviewed-by: Javier Martinez Canillas <javier@osg.samsung.com>