defrag: pass u64 to ParseU64

Fixes: defrag-config.c:97: warning: passing argument 2 \
       of 'ParseSizeStringU64' from incompatible pointer type

src/defrag-config.c

@@ -89,7 +89,7 @@ int DefragPolicyGetHostTimeout(Packet *p)
 static void DefragParseParameters(ConfNode *n)
 {
     ConfNode *si;
-    uintmax_t timeout = 0;
+    uint64_t timeout = 0;
 
     TAILQ_FOREACH(si, &n->head, next) {
         if (strcasecmp("timeout", si->name) == 0) {