Improve the libmix parser efficiency by using short format

BZ: 146002

On baytrail, the GEN hardware support AVC short format parsing.
In multiple slice situation, the parsing work is a bottleneck for
CPU. If we use AVC short format, some slice header parsing work
can be done with GEN HW. This will increase the overall decoding
performance.

Change-Id: Ib2bff7f4cca6cde917700e501ee53e3f17c55a81
Signed-off-by: wfeng6 <wei.feng@intel.com>
Reviewed-on: http://android.intel.com:8080/140127
Reviewed-by: Shi, PingX <pingx.shi@intel.com>
Tested-by: Shi, PingX <pingx.shi@intel.com>
Reviewed-by: cactus <cactus@intel.com>
Tested-by: cactus <cactus@intel.com>
6 files changed