avcodec/mpeg4videodec: copy rvlc in mpeg4_update_thread_context too

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/mpeg4videodec.c

@@ -2524,6 +2524,7 @@ static int mpeg4_update_thread_context(AVCodecContext *dst,
     s->shape               = s1->shape;
     s->time_increment_bits = s1->time_increment_bits;
     s->vol_sprite_usage    = s1->vol_sprite_usage;
+    s->rvlc                = s1->rvlc;
 
     return 0;
 }