tools/target_dec_fuzzer: Adjust threshold for screenpresso

Fixes: Timeout (332 -> 21 sec)
Fixes: 20280/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_SCREENPRESSO_fuzzer-6238663432470528

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

tools/target_dec_fuzzer.c

@@ -161,6 +161,7 @@ int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
     case AV_CODEC_ID_RASC:        maxpixels  /= 16;    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;
     case AV_CODEC_ID_SMACKVIDEO:  maxpixels  /= 64;    break;
     case AV_CODEC_ID_SNOW:        maxpixels  /= 128;   break;
     case AV_CODEC_ID_TGV:         maxpixels  /= 32;    break;