mmvideo.c: Remove unused variable in mm_decode_pal().

libavcodec/mmvideo.c:87:9: warning: variable ‘i’ set but not used

libavcodec/mmvideo.c

@@ -84,8 +84,7 @@ static int mm_decode_pal(MmContext *s)
  */
 static int mm_decode_intra(MmContext * s, int half_horiz, int half_vert)
 {
-    int i, x, y;
-    i=0; x=0; y=0;
+    int x = 0, y = 0;
 
     while (bytestream2_get_bytes_left(&s->gb) > 0) {
         int run_length, color;