ARM: dts: sun9i: a80: Add Security System node

The Security System is a hardware cryptographic accelerator that support
AES/MD5/SHA1/DES/3DES/PRNG/RSA algorithms.
It could be found on Allwinner SoC A80 and A83T

This patch adds it on the Allwinner A80 SoC Device-tree.

Signed-off-by: Corentin Labbe <clabbe.montjoie@gmail.com>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>