Request cold reboot when switching to dev mode

When switching from normal to dev mode, the EC is in RO. AP requests
warm reboot, whic causes EC to jump to RW. After sysjump, RW tries to
renegotiate PD but it's too late for type-c monitor to function
because VBIOS has already run.

This patch makes AP request EC reboot when switching to dev mode.

BUG=b:73083750
BRANCH=none
TEST=Dingdong connected to Teemo. Verify norm-to-dev screen is
displayed. make -j runtests.

Change-Id: I763cd6968406f7b904604b2588a9db6d567cbd4e
Signed-off-by: Daisuke Nojiri <dnojiri@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/907734
(cherry picked from commit c7293182ed0dd01004e2ed0e1e2a02eab0c52f93)
Reviewed-on: https://chromium-review.googlesource.com/908768
2 files changed