avformat: remove cast to void * (cherry picked from commit...

avformat: remove cast to void * (cherry picked from commit 91899a03)
Signed-off-by: KO Myung-Hun <komh@chollian.net>
Signed-off-by: Rafaël Carré <funman@videolan.org>

modules/demux/avformat/mux.c

@@ -224,7 +224,7 @@ static int AddStream( sout_mux_t *p_mux, sout_input_t *p_input )
     codec = stream->codec;
 
     /* This is used by LibavutilCallback (avutil.h) to print messages */
-    codec->opaque = (void*)p_mux;
+    codec->opaque = p_mux;
 
     switch( p_input->p_fmt->i_cat )
     {