BT: Handle Duplicate SHO request from AVRCP

- Race condition arise out of UI based SHO and
  play based SHO can result in duplicate SHO
  processing for same device.
- Earlier this condition was handled at A2DP
  level.
- With new design, this condition is being
  handled ay entry point. So, A2DP is handling
  for UI based SHO and AVRCP is handling for
  play-based SHO.

CRs-Fixed: 2588019

Change-Id: I5f01c0135aab3011ab1c60fe8ccd092406c9d381