AVRCP: Various improvements and fixes wrt AVRCP volume

- Update Absolute volume update to AudioManager based
on A2DP Active device during RC Feature update.

- In case of Blacklist Absolute volume devices update
must be informed as false i.e. unsupported.

- Race condition between SetVolumeFlag and SetActive
device fetch the volume from stored volume database.

Change-Id: I318ddce8efaa0cc10a7e429f5c0f984bb3afc5ef
1 file changed