ims_isc: clean gcc warnings

mark.c:341:9: warning: format ‘%zu’ expects argument of type ‘size_t’, but argument 10 has type ‘int’ [-Wformat]
mark.c:341:9: warning: format ‘%zu’ expects argument of type ‘size_t’, but argument 8 has type ‘int’ [-Wformat]
mark.c:341:1: warning: format ‘%zu’ expects argument of type ‘size_t’, but argument 8 has type ‘int’ [-Wformat]
mark.c:341:1: warning: format ‘%zu’ expects argument of type ‘size_t’, but argument 6 has type ‘int’ [-Wformat]
mark.c:350:9: warning: format ‘%zu’ expects argument of type ‘size_t’, but argument 10 has type ‘int’ [-Wformat]
mark.c:350:9: warning: format ‘%zu’ expects argument of type ‘size_t’, but argument 8 has type ‘int’ [-Wformat]
mark.c:350:1: warning: format ‘%zu’ expects argument of type ‘size_t’, but argument 8 has type ‘int’ [-Wformat]
mark.c:350:1: warning: format ‘%zu’ expects argument of type ‘size_t’, but argument 6 has type ‘int’ [-Wformat]
mark.c:357:9: warning: format ‘%zu’ expects argument of type ‘size_t’, but argument 13 has type ‘int’ [-Wformat]
mark.c:357:9: warning: format ‘%zu’ expects argument of type ‘size_t’, but argument 11 has type ‘int’ [-Wformat]
mark.c:357:1: warning: format ‘%zu’ expects argument of type ‘size_t’, but argument 11 has type ‘int’ [-Wformat]
mark.c:357:1: warning: format ‘%zu’ expects argument of type ‘size_t’, but argument 9 has type ‘int’ [-Wformat]

modules/ims_isc/mark.c

@@ -313,7 +313,7 @@ inline int isc_mark_write_route(struct sip_msg *msg, str *as, str *iscmark) {
  */
 int isc_mark_write_psu(struct sip_msg *msg, isc_mark *mark) {
     struct lump *l = msg->add_rm;
-    int hlen;
+    size_t hlen;
     char * hstr = NULL;
     const str *regstate, *sescase;