gralloc: do not use GNU old-style field designators

Avoiding the use of gnu extensions improves code portability

Change-Id: Icf8e3d4813bcddff40548bb5e65e615f8697b75c
gralloc: delete unused mutex declaration

Change-Id: Ibc7e70887b61f7dd885c86d412387636d3a6a867
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