tools/target_dec_fuzzer: Adjust threshold for SGA

Fixes: Timeout
Fixes: 382804863/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_SGA_fuzzer-5652795669151744

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

@@ -293,6 +293,7 @@ int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
     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_SGA_VIDEO:   maxpixels  /= 256;   break;
     case AV_CODEC_ID_SIMBIOSIS_IMX:maxpixels /= 16384; break;
     case AV_CODEC_ID_SPEEX:       maxsamples /= 128;   break;
     case AV_CODEC_ID_SMACKAUDIO:  maxsamples /= 4096;  break;