libsensors: add SensorTek ALS22x7 light sensor + cleanup

Change-Id: Ic6d7d4b279dc384255e897fece58bd5d62b02d16
overlay: setup light levels for auto brightness

Change-Id: I5a7f256387063d707d6b88c0aa38a0c1587c387d
Merge remote-tracking branch 'kf/cm-10.1-k34' into cm-10.1-k34