aacdec: change type of data in decode_audio_specific_config parameters

AVCodecContext.extradata is uint8_t*, silence a warning

Originally committed as revision 25644 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/aacdec.c

@@ -456,7 +456,7 @@ static int decode_ga_specific_config(AACContext *ac, AVCodecContext *avctx,
 static int decode_audio_specific_config(AACContext *ac,
                                         AVCodecContext *avctx,
                                         MPEG4AudioConfig *m4ac,
-                                        void *data, int data_size)
+                                        const uint8_t *data, int data_size)
 {
     GetBitContext gb;
     int i;