avcodec/error_resilience: Remove write only ERContext.ref_count

Reviewed-by: Michael Niedermayer <michael@niedermayer.cc>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

libavcodec/error_resilience.h

@@ -81,7 +81,6 @@ typedef struct ERContext {
     uint16_t pb_time;
     int quarter_sample;
     int partitioned_frame;
-    int ref_count;
 
     void (*decode_mb)(void *opaque, int ref, int mv_dir, int mv_type,
                       int (*mv)[2][4][2],

libavcodec/h264dec.c

@@ -776,8 +776,6 @@ end:
         if (sl->ref_count[1])
             ff_h264_set_erpic(&h->er.next_pic, sl->ref_list[1][0].parent);
 
-        h->er.ref_count = sl->ref_count[0];
-
         ff_er_frame_end(&h->er);
         if (use_last_pic)
             memset(&sl->ref_list[0][0], 0, sizeof(sl->ref_list[0][0]));