audio: Implement GetAudioConfig for HAL 2.1

This adds implementation for getting HAL 2.1 audio configuration.

Bug: 150670922
Tag: #feature
Test: vts-tradefed run vts -m VtsHalBluetoothAudioV2_1TargetTest
Sponsor: jpawlowski@
Change-Id: I12bbd0b9219e4d6f8328fd514536ce9ee477b757
3 files changed