Cosmetics: Fix a comment.

git-svn-id: file:///var/local/repositories/ffmpeg/trunk@22533 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b

libavcodec/vdpau.c

 /*
  * Video Decode and Presentation API for UNIX (VDPAU) is used for
- * HW decode acceleration for MPEG-1/2, H.264 and VC-1.
+ * HW decode acceleration for MPEG-1/2, MPEG-4 ASP, H.264 and VC-1.
  *
  * Copyright (c) 2008 NVIDIA
  *