Revert "AudioService: fix safe volume enforced even when disabled"

This reverts commit 5c2b579f432cff32ac0f0c5fb1d00f40db01cca5.
Add CPU boosting hooks

 * Send boost hint during scrolling
 * Still relevant on even high-end hardware

Change-Id: I72f2c2851b01fbceabddead03a4c3a7a0526ca61