sub: reset sub decoder correctly when cycling subtitles

reset_subtitles() works in mpctx->d_sub[], which is set to NULL before
calling it from uninit_sub(). This fixes resetting the subtitle when
cycling subtitle tracks.

Actually, this was probably a feature, because it's annoying if
subtitles don't show up when cycling them. But it also can have
unintended consequences, so get rid of it.

player/sub.c

@@ -146,10 +146,8 @@ void uninit_stream_sub_decoders(struct demuxer *demuxer)
 void uninit_sub(struct MPContext *mpctx, int order)
 {
     if (mpctx->d_sub[order]) {
-        mpctx->d_sub[order] = NULL; // Note: not free'd.
-        int obj = order ? OSDTYPE_SUB2 : OSDTYPE_SUB;
-        osd_set_sub(mpctx->osd, obj, NULL);
         reset_subtitles(mpctx, order);
+        mpctx->d_sub[order] = NULL; // Note: not free'd.
         reselect_demux_streams(mpctx);
     }
 }