audio: Add support for FLAC in compress offload path

- Add new audio format for FLAC
- Add FLAC in valid formats list
- Add bitWidth in offload info

Change-Id: Ic716aff8b7cdb28b03f32f686eca33ff0beb981c
Merge pull request #12 from CyanogenMod/cm-11.0

audio: Add support for FLAC in compress offload path