Add cold reset function

Cold reset function takes the AP through S0->S5->S0 reset
using 0xcf9 interface

BUG=b:150215069, crbug:1072877
TEST=None

Change-Id: I0769004928ad5d94cc6bea9a73a814b98381afef
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/coreboot/+/2322601
Tested-by: Dossym Nurmukhanov <dossym@chromium.org>
Auto-Submit: Dossym Nurmukhanov <dossym@chromium.org>
Commit-Queue: Furquan Shaikh <furquan@chromium.org>
Reviewed-by: Furquan Shaikh <furquan@chromium.org>
2 files changed