Verify AudioTrack only uses a valid multichannel configuration

Enforce the same rules as for HDMI output:
- FL/FR must be present
- paired channels must be used in pairs (e.g. no rear left
   without rear right)

Bug 6392126

Change-Id: I0a39e474dcf509cb7eabd8edd1f0e44852d72b51
1 file changed