Revert "audioflinger: Add missing code for FM volume"

This is no longer needed since the KK hal is merged now.

This reverts commit 79ddf29a5d9b4b8f865e2d997ce04fb67ceacbad.

Change-Id: I67ea91b10ccd1acc465d60704f13df77c59c7dd0
Merge "Revert "audioflinger: Add missing code for FM volume"" into android-4.4