libmix: VP8 parser refinement

BZ: 131068

This patch refined content:
1. add trace in parser if meet error
2. remove non-used function

Change-Id: Ib5c7520f0e55a4ed1ba59c41c4c131d9f2dd4ebb
Reviewed-on: http://android.intel.com:8080/139257
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>
4 files changed