Device tunables: Directly launch 'Device Settings' if available

Revert "CF: add device settings hook"

This reverts commit d9f66a70f34655ec2a536fcb6ce3fc740d6f1ce8.

Change-Id: I3f2dca06a24704cbc122c61925cb0ff9c18db9b2
Merge remote-tracking branch 'carbon/kk' into kitkat