Disable AVRCP position change in silence mode

* Save the silence mode information in BtifAvPeer send from
  JAVA, which helps AVRCP devices to check whether device
  silence mode is enabled or not.
* Stop sending AVRCP position change event to remote when
  silence mode is enabled.

Bug: 112323989
Test: Manual
Change-Id: I99d88a31caea062790c4ff0dc9199ed82f058067