avformat/westwood_vqa: Fix 2g packets

Fixes: signed integer overflow: 2147483424 * 2 cannot be represented in type 'int'
Fixes: 62276/clusterfuzz-testcase-minimized-ffmpeg_dem_WSVQA_fuzzer-4576211411795968

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavformat/westwood_vqa.c

@@ -262,7 +262,7 @@ static int wsvqa_read_packet(AVFormatContext *s,
                     break;
                 case SND2_TAG:
                     /* 2 samples/byte, 1 or 2 samples per frame depending on stereo */
-                    pkt->duration = (chunk_size * 2) / wsvqa->channels;
+                    pkt->duration = (chunk_size * 2LL) / wsvqa->channels;
                     break;
                 }
                 break;