mpeg: Mark ff_mpeg_set_erpic() static

It is not used outside of the file.

libavcodec/mpegvideo.c

@@ -2468,7 +2468,7 @@ void ff_MPV_report_decode_progress(MpegEncContext *s)
 }
 
 #if CONFIG_ERROR_RESILIENCE
-void ff_mpeg_set_erpic(ERPicture *dst, Picture *src)
+static void set_erpic(ERPicture *dst, Picture *src)
 {
     int i;
 
@@ -2494,9 +2494,9 @@ void ff_mpeg_er_frame_start(MpegEncContext *s)
 {
     ERContext *er = &s->er;
 
-    ff_mpeg_set_erpic(&er->cur_pic, s->current_picture_ptr);
-    ff_mpeg_set_erpic(&er->next_pic, s->next_picture_ptr);
-    ff_mpeg_set_erpic(&er->last_pic, s->last_picture_ptr);
+    set_erpic(&er->cur_pic,  s->current_picture_ptr);
+    set_erpic(&er->next_pic, s->next_picture_ptr);
+    set_erpic(&er->last_pic, s->last_picture_ptr);
 
     er->pp_time           = s->pp_time;
     er->pb_time           = s->pb_time;

libavcodec/mpegvideo.h

@@ -725,7 +725,6 @@ void ff_set_qscale(MpegEncContext * s, int qscale);
 
 /* Error resilience */
 void ff_mpeg_er_frame_start(MpegEncContext *s);
-void ff_mpeg_set_erpic(ERPicture *dst, Picture *src);
 
 int ff_dct_common_init(MpegEncContext *s);
 void ff_convert_matrix(DSPContext *dsp, int (*qmat)[64], uint16_t (*qmat16)[2][64],