TWSP-HFP: update BVRA state to both earbuds (2/2)

 - When VR is initiated/ended from earbud, response OK/ERROR to
   the requesting earbud, and send +BVRA to the other earbud while
   response OK.
 - When VR is initiated/ended from phone UI, send +BVRA to both
   earbuds.

Change-Id: Ifc5479a98d36421bc340b780db4a324ca709f7a5
CRs-Fixed: 2478343
2 files changed