avframe: have av_frame_get_side_data take const AVFrame*

Signed-off-by: Anton Khirnov <anton@khirnov.net>

libavutil/frame.c

@@ -465,7 +465,7 @@ AVFrameSideData *av_frame_new_side_data(AVFrame *frame,
     return ret;
 }
 
-AVFrameSideData *av_frame_get_side_data(AVFrame *frame,
+AVFrameSideData *av_frame_get_side_data(const AVFrame *frame,
                                         enum AVFrameSideDataType type)
 {
     int i;

libavutil/frame.h

@@ -485,7 +485,7 @@ AVFrameSideData *av_frame_new_side_data(AVFrame *frame,
  * @return a pointer to the side data of a given type on success, NULL if there
  * is no side data with such type in this frame.
  */
-AVFrameSideData *av_frame_get_side_data(AVFrame *frame,
+AVFrameSideData *av_frame_get_side_data(const AVFrame *frame,
                                         enum AVFrameSideDataType type);
 
 #endif /* AVUTIL_FRAME_H */