lavfi/fieldorder: remove pal8 format

Signed-off-by: Paul B Mahol <onemda@gmail.com>

libavfilter/vf_fieldorder.c

@@ -52,6 +52,7 @@ static int query_formats(AVFilterContext *ctx)
         for (pix_fmt = 0; pix_fmt < AV_PIX_FMT_NB; pix_fmt++) {
             const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(pix_fmt);
             if (!(desc->flags & AV_PIX_FMT_FLAG_HWACCEL ||
+                  desc->flags & AV_PIX_FMT_FLAG_PAL     ||
                   desc->flags & AV_PIX_FMT_FLAG_BITSTREAM) &&
                 desc->nb_components && !desc->log2_chroma_h &&
                 (ret = ff_add_format(&formats, pix_fmt)) < 0) {