tools/target_dec_fuzzer: Adjust RV60 threshold

Fixes: Timeout
Fixes: 410324670/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_RV60_fuzzer-5697706586865664

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

@@ -292,6 +292,7 @@ int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
     case AV_CODEC_ID_RASC:        maxpixels  /= 256;   break;
     case AV_CODEC_ID_RTV1:        maxpixels  /= 16;    break;
     case AV_CODEC_ID_RV30:        maxpixels  /= 256;   break;
+    case AV_CODEC_ID_RV60:        maxpixels  /= 256;   break;
     case AV_CODEC_ID_SANM:        maxpixels  /= 16;    break;
     case AV_CODEC_ID_SCPR:        maxpixels  /= 32;    break;
     case AV_CODEC_ID_SCREENPRESSO:maxpixels  /= 64;    break;