hammerhead: Configure sync_freq feature

Use the (optimized) sync_freq feature to stop frequency
jumping around, causing jitter. We may now even revert
timer_rate and timer_slack to the previous conservative
values.

Change-Id: Ie479a97d00d02b7f2b9867549848f1c251fcb642
hammerhead: Disable forced use of triple framebuffers

 * This can cause additional input latency and isn't really
   needed on this hardware.

Change-Id: I662915c08f9e8b9eef609319806feda880acc7a5
hammerhead: Enable use of FFMPEG codecs for extended formats

Change-Id: I1dc66749b6b5548c3617cbbfff389abc3d319562