lavc: move av_get_audio_frame_duration2() from avcodec.h to codec_par.h

doc/APIchanges

@@ -14,6 +14,9 @@ libavutil:     2021-04-27
 
 API changes, most recent first:
 
+2021-xx-xx - xxxxxxxxxx - lavc 59.1.100 - avcodec.h codec_par.h
+  Move av_get_audio_frame_duration2() from avcodec.h to codec_par.h.
+
 2021-xx-xx - xxxxxxxxxx - lavc 59.1.100 - avcodec.h codec_id.h
   Move av_get_bits_per_sample(), av_get_exact_bits_per_sample(),
   avcodec_profile_name(), and av_get_pcm_codec() from avcodec.h

libavcodec/avcodec.h

@@ -3121,12 +3121,6 @@ void avcodec_flush_buffers(AVCodecContext *avctx);
  */
 int av_get_audio_frame_duration(AVCodecContext *avctx, int frame_bytes);
 
-/**
- * This function is the same as av_get_audio_frame_duration(), except it works
- * with AVCodecParameters instead of an AVCodecContext.
- */
-int av_get_audio_frame_duration2(AVCodecParameters *par, int frame_bytes);
-
 /* memory */
 
 /**

libavcodec/codec_par.h

@@ -221,6 +221,11 @@ void avcodec_parameters_free(AVCodecParameters **par);
  */
 int avcodec_parameters_copy(AVCodecParameters *dst, const AVCodecParameters *src);
 
+/**
+ * This function is the same as av_get_audio_frame_duration(), except it works
+ * with AVCodecParameters instead of an AVCodecContext.
+ */
+int av_get_audio_frame_duration2(AVCodecParameters *par, int frame_bytes);
 
 /**
  * @}