[FM] FM volume will not be changed after stop and resume

    Launch FM Radio and play -> Change volume via keyboard from
    maximal to minimal/minimal to maximal -> Tap "Stop" button to
    stop FM -> Tap "Stop" button to resume FM -> Check the volume
    after resuming FM, FM volume will not change to the corresponding
    volume.

    We use MediaSession.setPlaybackToRemove(VolumeProvider vp) for
    audio patch getting volume update event from audio framework.
    The initial volume is not right, it needs to keep the same with
    stream STREAM_MUSIC.

    Bug 18762406

    Review: https://partner-android-review.git.corp.google.com/#/c/188807



Signed-off-by: Benson Huang <benson.huang@mediatek.com>

Change-Id: Ibbd82de6cf9e510a0c8e2cb9ded2fc34ca2db16e