cosmetics: Use C-style comments in #endif directives.

Originally committed as revision 13442 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/acelp_vectors.h

@@ -148,4 +148,4 @@ void ff_acelp_weighted_vector_sum(
         int shift,
         int length);
 
-#endif // FFMPEG_ACELP_VECTORS_H
+#endif /* FFMPEG_ACELP_VECTORS_H */