lavc/decode: drop a useless warning

Decoders will currently warn if an audio decoder not marked with
AV_CODEC_CAP_SUBFRAMES consumes less than the whole packet, but
* this happens for regular files
* this has no negative consequences
* there is no meeaningful action that can or should be taken in response

The warning is thus useless noise.

libavcodec/decode.c

@@ -423,13 +423,6 @@ FF_ENABLE_DEPRECATION_WARNINGS
         }
     }
 
-    if (avctx->codec->type == AVMEDIA_TYPE_AUDIO &&
-        !avci->showed_multi_packet_warning &&
-        ret >= 0 && ret != pkt->size && !(avctx->codec->capabilities & AV_CODEC_CAP_SUBFRAMES)) {
-        av_log(avctx, AV_LOG_WARNING, "Multiple frames in a packet.\n");
-        avci->showed_multi_packet_warning = 1;
-    }
-
     if (!got_frame)
         av_frame_unref(frame);
 

libavcodec/internal.h

@@ -148,8 +148,6 @@ typedef struct AVCodecInternal {
     AVFrame *buffer_frame;
     int draining_done;
 
-    int showed_multi_packet_warning;
-
     /* to prevent infinite loop on errors when draining */
     int nb_draining_errors;