lavf/mxfenc: Do not print a useless error message.

The option d10_channelcount only exists for mxf_d10.

libavformat/mxfenc.c

@@ -1169,8 +1169,6 @@ static void mxf_write_generic_sound_common(AVFormatContext *s, AVStream *st, con
             av_log(s, AV_LOG_WARNING, "d10_channelcount shall be set to 4 or 8 : the output will not comply to MXF D-10 specs\n");
         avio_wb32(pb, mxf->channel_count);
     } else {
-        if (show_warnings && mxf->channel_count != -1 && s->oformat != &ff_mxf_opatom_muxer)
-            av_log(s, AV_LOG_ERROR, "-d10_channelcount requires MXF D-10 and will be ignored\n");
         avio_wb32(pb, st->codecpar->channels);
     }