typo

git-svn-id: file:///var/local/repositories/ffmpeg/trunk@11637 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b

libavcodec/libamr.c

@@ -523,7 +523,7 @@ AVCodec libamr_nb_encoder =
 #ifdef CONFIG_LIBAMR_WB
 
 #ifdef _TYPEDEF_H
-//To avoid duplicate typedefs from typdef in amr-nb
+//To avoid duplicate typedefs from typedef in amr-nb
 #define typedef_h
 #endif