Extended volume panel: Give ringer volume it's own set of icons

Since all we have to indicate which volume we're controlling in the Extended
Volume Panel, is the icon - each volume slider should probably have it's own
icon (to distinguish what is what). That's the purpose of this change.

Change-Id: Iafbc0f8c940c601ee8745fc666b1ea39b4d8bb4b
3 files changed