Bring back DeviceSettings

Revert "smdk4412: hardware tunables: vibrator support"

This reverts commit a7af906ca79a886b863bb0c419b9f9ee2745682e.

Revert "smdk4412: remove DeviceSettings"

This reverts commit 006c95d4f0c75b9bdf3827856dc694d973464520.

Change-Id: I98fb1e977e3436eb3d717dc284b841f27ee2eac0