hammerhead: Enable ZSL mode for camera

 * With recent kernel changes, we no longer crash when letting the
   preview run during continuous shots. Enjoy rapid-fire shooting.

Change-Id: Ib57869f185166539d761fd5a2766c586501023da
Revert "Revert "hammerhead: Enable deep buffer output as primary""

 * This is working as intended now. Tested with Hangouts and other apps.
 * The purpose of this change is so that media playback uses the deep
   buffer path instead of the low-latency path, which uses much more
   power.

This reverts commit 22dde6a88e7b5453f39d96a23c65a3cd5d4dc085.

Change-Id: I476dd429be4b7c74acd888169004ed89081597c7
hammerhead: Add offload properties

 * Set fragment size (same as default)
 * Enable gapless playback with offloaded streams
 * Enable offloading for AV (but not streaming AV!)

Change-Id: I1b0f8115bc880bd89f5a0c8ed13e4b54d38e0867
hammerhead: Enable new mixer for offload

Change-Id: I21620d3a2612c992dc70a783f20aa8b73e8c9073