Use SIZE_T for length limiter

xtoskrnl/rtl/widestr.c

@@ -29,9 +29,9 @@ XTCDECL
 INT
 RtlWideStringCompare(IN CONST PWCHAR String1,
                      IN CONST PWCHAR String2,
-                     IN CONST ULONG Length)
+                     IN CONST SIZE_T Length)
 {
-    ULONG Index;
+    SIZE_T Index;
 
     /* Iterate through the strings */
     for(Index = 0; ; Index++) {