Move av_div_i()'s comments to the header file. The comments are unaltered.

Originally committed as revision 8227 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavutil/integer.h

@@ -47,6 +47,10 @@ AVInteger av_shr_i(AVInteger a, int s);
  * @param quot a/b will be stored here
  */
 AVInteger av_mod_i(AVInteger *quot, AVInteger a, AVInteger b);
+
+/**
+ * returns a/b.
+ */
 AVInteger av_div_i(AVInteger a, AVInteger b);
 AVInteger av_int2i(int64_t a);
 int64_t av_i2int(AVInteger a);