refactor(cpus): convert the Cortex-A76AE to use cpu helpers

Signed-off-by: Govindraj Raja <govindraj.raja@arm.com>
Change-Id: I72627afd0e2f10fb754d5c0de137fc9714ed391f
(cherry picked from commit 91ba1a5edf1983c61455972e58287299bb53fc1b)
1 file changed