Add AES crypto library

Add support for AES using an implementation from Karl Malbrain.
This offers small code size (around 5KB on ARM) and supports 128-bit
AES only.

Signed-off-by: Yen Lin <yelin@nvidia.com>
Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Warren <twarren@nvidia.com>