tools/target_dec_fuzzer: Adjust threshold for lagarith

Fixes: Timeout (3minute 49 sec -> 3sec)
Fixes: 22020/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_LAGARITH_fuzzer-5708544679870464

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

@@ -159,6 +159,7 @@ int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
     case AV_CODEC_ID_HNM4_VIDEO:  maxpixels  /= 128;   break;
     case AV_CODEC_ID_IFF_ILBM:    maxpixels  /= 128;   break;
     case AV_CODEC_ID_INDEO4:      maxpixels  /= 128;   break;
+    case AV_CODEC_ID_LAGARITH:    maxpixels  /= 1024;  break;
     case AV_CODEC_ID_LSCR:        maxpixels  /= 16;    break;
     case AV_CODEC_ID_MOTIONPIXELS:maxpixels  /= 256;   break;
     case AV_CODEC_ID_MP4ALS:      maxsamples /= 65536; break;