FP3: audio: Cleanup duplicate files

* audio_output_policy.conf and audio_policy.conf are now used
from the new audio HAL project.
* audio_platform_info_extcodec.xml is renamed to audio_platform_info_sku3_tasha.xml
and used from the new audio HAL project.
* Move audio firmware files to proprietary-files
* Update audio configuration and mixer path file
from stock audio HAL project.

Change-Id: Ie5d1985d4fe46d775ada5259292ea4673d2dd3bb