audiopolicy: Use AUDIO_OUTPUT_FLAG_TTS for TTS stream

Use AUDIO_OUTPUT_FLAG_TTS by default for TTS stream to see
if the HW supports a dedicated output for the same. If not,
fallback to primary output as it is done currently.

Change-Id: Ifb2ef7066e75c61fe4c1b9783c12627386a00ea5
1 file changed