Remove volume buttons music control.

The currently kitkat implementation is currently half-broken around. The skipping track delay is noticeable, also the display sometimes wakes up when both wake screen and music control options are on.
The feature is hardcoded so enabled and part of the system. We don't want broken stuffs so just remove this for now.

Signed-off-by: Carlo Savignano <stevewatersy@gmail.com>