Move doxygen comments for av_gettime from utils.c to avformat.h.

Originally committed as revision 15439 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/avformat.h

@@ -1034,6 +1034,7 @@ attribute_deprecated int parse_frame_rate(int *frame_rate, int *frame_rate_base,
  */
 int64_t parse_date(const char *datestr, int duration);
 
+/** Gets the current time in microseconds. */
 int64_t av_gettime(void);
 
 /* ffm specific for ffserver */

libavformat/utils.c

@@ -2853,9 +2853,6 @@ int parse_frame_rate(int *frame_rate_num, int *frame_rate_den, const char *arg)
     return ret;
 }
 
-/**
- * Gets the current time in microseconds.
- */
 int64_t av_gettime(void)
 {
     struct timeval tv;