qsvdec: set complete_frame flags for non-interlaced frames.

This can fix vc1 decoding segment fault issues.
See: ./ffmpeg -hwaccel qsv -c:v vc1_qsv -i /fate-suite/vc1/SA00040.vc1
-vf "hwdownload, format=nv12" -f rawvideo /dev/null

Signed-off-by: Zhong Li <zhong.li@intel.com>

Author: lizhong1008

libavcodec/qsvdec.c

@@ -310,6 +310,9 @@ static int qsv_decode(AVCodecContext *avctx, QSVContext *q,
         bs.DataLength = avpkt->size;
         bs.MaxLength  = bs.DataLength;
         bs.TimeStamp  = avpkt->pts;
+        if (avctx->field_order == AV_FIELD_UNKNOWN ||
+            avctx->field_order == AV_FIELD_PROGRESSIVE)
+            bs.DataFlag   |= MFX_BITSTREAM_COMPLETE_FRAME;
     }
 
     sync = av_mallocz(sizeof(*sync));