scarlet: Fix Z axis for accelerometer
scarlet: Fix Z axis for accelerometer

The Z axis is a little trickier, it's not always obvious that it's backwards.
"ectool motionsense" should show +1g on Z when display is pointing up.

BRANCH=gru
BUG=b:62307687
CQ-DEPEND=CL:524982
TEST=Put display up, "ectool motionsense" shows a largeish
positive value on Z for sensor 0:
localhost ~ # ectool motionsense
Sensor 0: 428   504     17069

Change-Id: I39ee6d524ba907570c85bf9e2fe248e029561999
Signed-off-by: Alexandru M Stan <1784cbba6d7675b1eba55eaefe41c7672ad9da3b@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/451692
Reviewed-by: Aseda Aboagye <12c9b286316a940fd31c24070da5ab64cdd4d0e7@chromium.org>
Commit-Queue: Philip Chen <3ee404f9ef892bc3fda6e6a76e65843b5fa44db2@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/524984
Commit-Ready: Philip Chen <3ee404f9ef892bc3fda6e6a76e65843b5fa44db2@chromium.org>
Tested-by: Philip Chen <3ee404f9ef892bc3fda6e6a76e65843b5fa44db2@chromium.org>
Reviewed-by: Philip Chen <3ee404f9ef892bc3fda6e6a76e65843b5fa44db2@chromium.org>

coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec