platform/chrome: lightbar: Get drvdata from parent in suspend/resume

The lightbar driver never assigned the drvdata in probe method, and
thus there is nothing there. Need to get the ec_dev from the parent's
drvdata.

Signed-off-by: Rajat Jain <rajatja@google.com>
Reviewed-by: Gwendal Grignou <gwendal@chromium.org>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>