tools/target_dec_fuzzer: Adjust threshold for wavpack

Fixes: Timeout (long -> 4sec)
Fixes: 29064/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_WAVPACK_fuzzer-5104450901508096

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

tools/target_dec_fuzzer.c

@@ -193,6 +193,7 @@ int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
     case AV_CODEC_ID_VMNC:        maxpixels  /= 8192;  break;
     case AV_CODEC_ID_VP7:         maxpixels  /= 256;   break;
     case AV_CODEC_ID_VP9:         maxpixels  /= 4096;  break;
+    case AV_CODEC_ID_WAVPACK:     maxsamples /= 1024;  break;
     case AV_CODEC_ID_WMV3IMAGE:   maxpixels  /= 8192;  break;
     case AV_CODEC_ID_WS_VQA:      maxpixels  /= 16384; break;
     case AV_CODEC_ID_WMALOSSLESS: maxsamples /= 1024;  break;