arm64: implement CPU power down sequence as per A57/A53/A72 TRM

Implement the individual core powerdown sequence as per
Cortex-A57/A53/A72 TRM.

Based-on-the-work-by:
Varun Wadekar <vwadekar@nvidia.com>

BRANCH=none
BUG=none
TEST=boot on smaug/foster, verify the cpu_on/off is ok as well

Change-Id: I4719fcbe86b35f9b448d274e1732da5fc75346b0
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Original-Commit-Id: b6bdcc12150820dfad28cef3af3d8220847c5d74
Original-Change-Id: I65abab8cda55cfe7a0c424f3175677ed5e3c2a1c
Original-Signed-off-by: Joseph Lo <josephl@nvidia.com>
Original-Reviewed-on: https://chromium-review.googlesource.com/265827
Original-Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/9980
Tested-by: build bot (Jenkins)
Reviewed-by: Marc Jones <marc.jones@se-eng.com>
5 files changed