avcodec/alsdec: Add FF_CODEC_CAP_INIT_CLEANUP

Fixes: multiple memleaks
Fixes: 15293/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_ALS_fuzzer-5642409288925184

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

libavcodec/alsdec.c

@@ -2127,7 +2127,6 @@ static av_cold int decode_init(AVCodecContext *avctx)
     return 0;
 
 fail:
-    decode_end(avctx);
     return ret;
 }
 
@@ -2153,4 +2152,5 @@ AVCodec ff_als_decoder = {
     .decode         = decode_frame,
     .flush          = flush,
     .capabilities   = AV_CODEC_CAP_SUBFRAMES | AV_CODEC_CAP_DR1,
+    .caps_internal  = FF_CODEC_CAP_INIT_CLEANUP,
 };