Remove stray Doxygen grouping command; fixes one Doxygen warning.

Originally committed as revision 23996 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/vdpau.h

@@ -38,7 +38,6 @@
  * and rendering (API calls) are done as part of the VDPAU
  * presentation (vo_vdpau.c) module.
  *
- * @{
  * \defgroup  VDPAU_Decoding VDPAU Decoding
  * \ingroup Decoder
  * @{