avcodec/aac/aacdec_usac: Clean ics2->max_sfb when first SCE fails

Fixes: out of array access
Fixes: 70734/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_AAC_LATM_fuzzer-4741427068731392
Fixes: 383194070/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_AAC_LATM_fuzzer-5302387708854272

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

libavcodec/aac/aacdec_usac.c

@@ -917,8 +917,10 @@ static int decode_usac_stereo_info(AACDecContext *ac, AACUSACConfig *usac,
         }
 
         ret = setup_sce(ac, sce1, usac);
-        if (ret < 0)
+        if (ret < 0) {
+            ics2->max_sfb = 0;
             return ret;
+        }
 
         ret = setup_sce(ac, sce2, usac);
         if (ret < 0)