Add VTS for the audio primary device

Its base class was tested but not the primary
device getters and setters.

Test: run the corresponding vts test
Test: vts-tradefed r vts-hal-hidl -m VtsHalAudioV2_0Target

Bug: 34170075
Change-Id: Ic451761c7b8b29fd302a62aba83be6ce7be35f64
Signed-off-by: Kevin Rocard <krocard@google.com>