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
Merge remote-tracking branch 'cm/cm-11.0' into cm-11.0