input: misc: stk3x1x: turn off device power when sensor is not enabled

Device needs to turn off when both ambient light sensor and
proximity sensor is not enabled, this will maximize power saving.

Change-Id: I3195f180e065c1605029af37da4a65ce30612ac2
Signed-off-by: Bingzhe Cai <bingzhec@codeaurora.org>