feat(cpus): add support for cortex-a720ae

Add the basic CPU library code to support Cortex-A720AE.
The overall library code is adapted based on Cortex-A720 code.

Signed-off-by: David Hu <david.hu2@arm.com>
Signed-off-by: Ahmed Azeem <ahmed.azeem@arm.com>
Change-Id: I3d64dc5a3098cc823e656a5ad3ea05cd71598dc6
3 files changed