Audio HAL VTS: Some methods are not optional

Some mandatory methods were allowed to return NOT_SUPPORTED
although their implementations is mandatory.

Test: vts-tradefed run vts --module VtsHalAudioV2_0Target
Test: call/play music/record/video...
Bug: 36311550
Change-Id: Ibe4b3cf73257309975ed11269a38315051fa9064
Signed-off-by: Kevin Rocard <krocard@google.com>