net: tipc: Replace expression with offsetof()

Use the existing offsetof() macro instead of duplicating code.

Signed-off-by: Zheng Yongjun <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

net/tipc/monitor.c

···
  */
 static int dom_rec_len(struct tipc_mon_domain *dom, u16 mcnt)
 {
-	return ((void *)&dom->members - (void *)dom) + (mcnt * sizeof(u32));
+	return (offsetof(struct tipc_mon_domain, members)) + (mcnt * sizeof(u32));
 }
 
 /* dom_size() : calculate size of own domain based on number of peers