Drop redundant assignment and variable

Originally committed as revision 9502 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/vc1.c

@@ -89,9 +89,7 @@ static int get_prefix(GetBitContext *gb, int stop, int len)
 }
 
 static inline int decode210(GetBitContext *gb){
-    int n;
-    n = get_bits1(gb);
-    if (n == 1)
+    if (get_bits1(gb))
         return 0;
     else
         return 2 - get_bits1(gb);