avplay: drop -vismv option which does not do anything anymore

Changelog

@@ -43,6 +43,7 @@ version 10:
 - HNM version 4 demuxer and video decoder
 - HEVC decoder
 - raw HEVC, HEVC in MOV/MP4, HEVC in Matroska, HEVC in MPEG-TS demuxing
+- remove avplay -vismv option, which has not worked for a long time
 
 
 version 9:

avplay.c

@@ -242,7 +242,6 @@ static int show_status = 1;
 static int av_sync_type = AV_SYNC_AUDIO_MASTER;
 static int64_t start_time = AV_NOPTS_VALUE;
 static int64_t duration = AV_NOPTS_VALUE;
-static int debug_mv = 0;
 static int step = 0;
 static int workaround_bugs = 1;
 static int fast = 0;
@@ -2036,7 +2035,6 @@ static int stream_component_open(VideoState *is, int stream_index)
     opts = filter_codec_opts(codec_opts, avctx->codec_id, ic, ic->streams[stream_index], NULL);
 
     codec = avcodec_find_decoder(avctx->codec_id);
-    avctx->debug_mv          = debug_mv;
     avctx->workaround_bugs   = workaround_bugs;
     avctx->idct_algo         = idct;
     avctx->skip_frame        = skip_frame;
@@ -2812,12 +2810,6 @@ static int opt_duration(void *optctx, const char *opt, const char *arg)
     return 0;
 }
 
-static int opt_vismv(void *optctx, const char *opt, const char *arg)
-{
-    debug_mv = parse_number_or_die(opt, arg, OPT_INT64, INT_MIN, INT_MAX);
-    return 0;
-}
-
 static const OptionDef options[] = {
 #include "cmdutils_common_opts.h"
     { "x", HAS_ARG, { .func_arg = opt_width }, "force displayed width", "width" },
@@ -2837,7 +2829,6 @@ static const OptionDef options[] = {
     { "pix_fmt", HAS_ARG | OPT_EXPERT | OPT_VIDEO, { .func_arg = opt_frame_pix_fmt }, "set pixel format", "format" },
     { "stats", OPT_BOOL | OPT_EXPERT, { &show_status }, "show status", "" },
     { "bug", OPT_INT | HAS_ARG | OPT_EXPERT, { &workaround_bugs }, "workaround bugs", "" },
-    { "vismv", HAS_ARG | OPT_EXPERT, { .func_arg = opt_vismv }, "visualize motion vectors", "" },
     { "fast", OPT_BOOL | OPT_EXPERT, { &fast }, "non spec compliant optimizations", "" },
     { "genpts", OPT_BOOL | OPT_EXPERT, { &genpts }, "generate pts", "" },
     { "drp", OPT_INT | HAS_ARG | OPT_EXPERT, { &decoder_reorder_pts }, "let decoder reorder pts 0=off 1=on -1=auto", ""},

doc/avplay.texi

@@ -78,8 +78,6 @@ Show the stream duration, the codec parameters, the current position in
 the stream and the audio/video synchronisation drift.
 @item -bug
 Work around bugs.
-@item -vismv
-Visualize motion vectors.
 @item -fast
 Non-spec-compliant optimizations.
 @item -genpts