libhardware: Modify ifdefs for legacy DirectTrack

Change-Id: Id3a8adc3bd3b8fe5973e359b5268671f6fd26cd4
libhardware: Modify ifdefs for legacy DirectTrack

Summary:
Change-Id: Id3a8adc3bd3b8fe5973e359b5268671f6fd26cd4

libhardware: Add fix for offload playback.

-Offload mode requires frame size to be unity.
-Tunnel encode changes results in a invalid frame size being
 returned to audio flinger.
-Add 24 bit PCM format as exception to linear pcm.

Change-Id: I23d1960b0a493da20f48de788bb13e6f055ebe03

Test Plan: confirm compile and functionality on as many variants as possilbe

Reviewers: synergy, anders3408, jriordan001, raymanfx, donald.munn, rlasalle15

Differential Revision: http://review.codefirex.com/D283