[cleanup] Convert XMALLOC/memset to XCALLOC

Simple conversion of XMALLOC/memset to XCALLOC
diff --git a/zebra/irdp_interface.c b/zebra/irdp_interface.c
index dd77340..b3a838b 100644
--- a/zebra/irdp_interface.c
+++ b/zebra/irdp_interface.c
@@ -175,10 +175,7 @@
 
 struct Adv *Adv_new (void)
 {
-  struct Adv *new;
-  new = XMALLOC (MTYPE_TMP, sizeof (struct Adv));
-  memset (new, 0, sizeof (struct Adv));
-  return new;
+  return XCALLOC (MTYPE_TMP, sizeof (struct Adv));
 }
 
 static void