policy_hal: Update offload restrictions

 * Fix the PCM offload duration checks
 * Reject offloading for A2DP and USB devices in order to
   hit the fail-fast path in Stagefright- this allows transparent
   fallback to 16-bit PCM with resampling when necessary.

Change-Id: I26d1fd9d92f267c6875e98ef490e8d90bb442813
hal: Output latency optimization

 * Enable use of ultra low latency path when the FAST output
   is selected and a compatible stream is detected.
 * Add option to enable the low latency record path for
   experimentation purposes (other work is needed).
 * The ULL feature has several dependencies and does not work
   with all hardware. Do not enable this unless you know
   what you are doing.

Change-Id: I0f2e10008028935730da4c014ecaec50cf7fcd7b