lavu/utils: silence warnings about incompatible pointer types

Signed-off-by: Paul B Mahol <onemda@gmail.com>

libavutil/utils.c

@@ -99,7 +99,7 @@ unsigned av_int_list_length_for_size(unsigned elsize,
     if (!list)
         return 0;
 #define LIST_LENGTH(type) \
-    { type t = term, *l = list; for (i = 0; l[i] != t; i++); }
+    { type t = term, *l = (type *)list; for (i = 0; l[i] != t; i++); }
     switch (elsize) {
     case 1: LIST_LENGTH(uint8_t);  break;
     case 2: LIST_LENGTH(uint16_t); break;