Option to use volume keys to control media volume anytime [2/2]

The volume keys control the Media volume rather than the Ringer
hence removing the issue of accidentaly changing the Ringer volume.

Credits: Pawitp

Change-Id: Ic0a1c04ae41eac65e9535d6de5f11c0456730315
Merge commit 'refs/changes/54/854/2' of https://gerrit.slimroms.net/SlimRoms/packages_apps_Settings into vaosp