lavc: use avpriv_ prefix for ff_aac_parse_header().

It's used in lavf.

libavformat/spdifdec.c

@@ -57,7 +57,7 @@ static int spdif_get_offset_and_codec(AVFormatContext *s,
         break;
     case IEC61937_MPEG2_AAC:
         init_get_bits(&gbc, buf, AAC_ADTS_HEADER_SIZE * 8);
-        if (ff_aac_parse_header(&gbc, &aac_hdr)) {
+        if (avpriv_aac_parse_header(&gbc, &aac_hdr)) {
             if (s) /* be silent during a probe */
                 av_log(s, AV_LOG_ERROR, "Invalid AAC packet in IEC 61937\n");
             return AVERROR_INVALIDDATA;