avformat/(aiff|flac|mov|mp3|tta)enc: Don't create unnecessary references

The packet given to muxers is not used afterwards; it is always
unreferenced by libavformat. Ergo muxers are allowed to keep
the references in the packets and e.g. move the ownership to
a packet list. This is what this commit does.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

libavformat/aiffenc.c

@@ -219,7 +219,7 @@ static int aiff_write_packet(AVFormatContext *s, AVPacket *pkt)
             return 0;
 
         return avpriv_packet_list_put(&aiff->pict_list, &aiff->pict_list_end,
-                                  pkt, av_packet_ref, 0);
+                                      pkt, NULL, 0);
     }
 
     return 0;