avcodec/vc1dec: ff_print_debug_info() does not support WMV3 field_mode

Fixes: out of array read
Fixes: 36331/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_WMV3_fuzzer-5140494328922112.fuzz

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavcodec/vc1dec.c

@@ -1151,11 +1151,13 @@ image:
         if (s->pict_type == AV_PICTURE_TYPE_B || s->low_delay) {
             if ((ret = av_frame_ref(pict, s->current_picture_ptr->f)) < 0)
                 goto err;
+            if (!v->field_mode)
                 ff_print_debug_info(s, s->current_picture_ptr, pict);
             *got_frame = 1;
         } else if (s->last_picture_ptr) {
             if ((ret = av_frame_ref(pict, s->last_picture_ptr->f)) < 0)
                 goto err;
+            if (!v->field_mode)
                 ff_print_debug_info(s, s->last_picture_ptr, pict);
             *got_frame = 1;
         }