typo, also fix warning: asf.c:90: warning: passing argument 2 of 'get_buffer'...

typo, also fix warning: asf.c:90: warning: passing argument 2 of 'get_buffer' from incompatible pointer type

Originally committed as revision 11681 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/asf.c

@@ -87,7 +87,7 @@ static void print_guid(const GUID *g)
 static void get_guid(ByteIOContext *s, GUID *g)
 {
     assert(sizeof(*g) == 16);
-    get_buffer(s, g, sizeof(*g));
+    get_buffer(s, *g, sizeof(*g));
 }
 
 #if 0