hal: add custom platform abstraction

Change-Id: I7ce4a1b05e8957b43581242ec7e6f21f0ad900aa
alsa_sound: Raise priority of separate VOIP input

 * This needs to come first for devices that use this path, otherwise
   we fallthru to the standard voice call route.
 * Fixes Hangouts on JF.

Change-Id: I21fbdf520a5bb0e48b3c8988bc99c9cca0b64e85
hal: Allow enablment of COMPRESS_VOIP without multisession voice

 * It works!

Change-Id: Ie150055bd711a0060db91e50a47b7726f42cdc4e