detachables: Power button turns off device on RECOVERY_INSERT screen
detachables: Power button turns off device on RECOVERY_INSERT screen

BUG=b:64400325
BRANCH=None
TEST=boot up into recovery, press power button
     ensure device shuts down.

Change-Id: Ia8e6e91921e81692a2e57b1f77163c656b56ea85
Signed-off-by: Shelley Chen <ab7b8cc85923339aed379eb1c5cc4dccfd2eb3d7@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/646488
Reviewed-by: Julius Werner <4d12f06cff3725783b352157673a720bc67c4afe@chromium.org>

coreboot/vboot,coreboot/vboot,coreboot/vboot,coreboot/vboot,coreboot/vboot