A2dp: add handle for connected status event.

When Bluetooth is reenabled, Src peer and Snk peer can be at the connecting status at the same time,
that would cause both Src and Snk devices got connected. Add handle for connected status event can
avoid such cases.

CRs-Fixed: 2475478
Change-Id: Ie9743755d1bfcdd4e4e43dc28704b1459bbd05f2
2 files changed