CHROMIUM: config: enable BACKLIGHT_ARCXCNN on arm64

BUG=chrome-os-partner:55051
TEST=backlight lights up on gru rev2

Change-Id: Ie56d29985c90510926901d5c5b875233b245989c
Signed-off-by: Stephen Barber <smbarber@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/411953
Reviewed-by: Douglas Anderson <dianders@chromium.org>
(cherry picked from commit 9c9f3138dbdb811ec4ffbb17d6d67e2351cf48bc)
Reviewed-on: https://chromium-review.googlesource.com/412373
4 files changed