audio: changes for new audio device enums

Modifications for new audio device enums:
- Separated input and output device fields as output and input device
values are now on 32 bits.
- Changed audio device API version to 2.0

Also removed get_supported_devices() function not needed if audio_policy.conf
file is present.

Change-Id: I41b782e7450b4664048cc484a681b9327d8395da
1 file changed