BT: Update Volume Management logic during SHO

- Currently, volume is muted during the duration
  of the SHO to avoid volume leaks. MM-Audio
  mutes the volume when SHO starts and then unmute
  it when new device is configured.
- With current logic, mute gets delayed because
  SHO process starts at Bluetooth. This causes
  occasional leaks and volume related abnormal
  behaviors.

- With this change, Bluetooth will trigger the
  mute part during SHO to ensure the volume is
  muted for the entire duration of SHO process.
- Bluetooth will mute volume only when the
  streaming is active on previous active device.
- Further serialization has been done to ensure
  that new SHO process won't be initiated till
  last SHO is completed on the previous device
  when Music starts streaming on it.

CRs-Fixed: 2587968

Change-Id: Iba4a7c3c8a575a2fa5932ddb194daab58f9a9305
1 file changed