Bluetooth: Synchronize Virtual Call,Voice Call and A2dp

Found some IOT Issues were headsets behave abnormally if there is
START or SUSPEND over AVDTP in between call indicators sent for
Voip calls. This change will make sure A2dp is Suspended before
sending call indicators and Starts once the Virtual call is Ended.

Change-Id: Iaef6c08b593581112519e53a5d73086fd1539b99
CRs-fixed: 503739,516722