CHROMIUM: drm/bridge: control LCD and backlight FETs

CHROMIUM: drm/bridge: control LCD and backlight FETs

Ensure we are powering on and off the FETs controlling the backlight and
the LCD VDD.

Signed-off-by: Vincent Palatin <vpalatin@chromium.org>
BUG=chrome-os-partner:18122
TEST=on Spring, use "powerd_suspend" to suspend the machine, and check
the state of the TPS65090 FETs by using the "pmu" on the EC command
line.

Change-Id: I3a0d03fdac18b4d13de2d33de6ba2e0429dd0daf
Reviewed-on: https://gerrit.chromium.org/gerrit/44599
Reviewed-by: Todd Broch <tbroch@chromium.org>
Reviewed-by: Stéphane Marchesin <marcheu@chromium.org>
Commit-Queue: Vincent Palatin <vpalatin@chromium.org>
Tested-by: Vincent Palatin <vpalatin@chromium.org>