avformat/flvdec: remove duplicated line error

Fix typo regression since 5c37ffca

Found-By: cousin_luigi

libavformat/flvdec.c

@@ -441,7 +441,6 @@ static int amf_parse_object(AVFormatContext *s, AVStream *astream,
             if (amf_parse_object(s, astream, vstream, str_val, max_pos,
                                  depth + 1) < 0)
                 return -1;
-        if (avio_r8(ioc) != AMF_END_OF_OBJECT)
         if (avio_r8(ioc) != AMF_END_OF_OBJECT) {
             av_log(s, AV_LOG_ERROR, "Missing AMF_END_OF_OBJECT in AMF_DATA_TYPE_MIXEDARRAY\n");
             return -1;