h264dec: fix miss frame when negtive poc in stream

getOutputByMinPOC will return surface with smallest poc.
But surface pool use uint32_t hold poc.some bit stream have negtive poc, like CVMANL1_TOSHIBA_B.264.
The surface with negtive poc will never get chance to output
h264dec: support gaps between pictures.

Signed-off-by: Zhong Cong <congx.zhong@intel.com>
ih264dec: support gaps between pictures 2.

Signed-off-by: Zhong Cong <congx.zhong@intel.com>
h264dec: support gaps between pictures 3.

Signed-off-by: Zhong Cong <congx.zhong@intel.com>
h264dec: support gaps between pictures 4.

Signed-off-by: Zhong Cong <congx.zhong@intel.com>

Conflicts:
	decoder/vaapidecoder_h264.cpp
h264dec: support gaps between pictures 5.

Signed-off-by: Zhong Cong <congx.zhong@intel.com>
h264dec: support gaps between pictures 6.

Signed-off-by: Zhong Cong <congx.zhong@intel.com>