net: use IS_ENABLED(CONFIG_IPV6)

Instead of testing defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/xfrm4_tunnel.c b/net/ipv4/xfrm4_tunnel.c
index 8280645..9247d9d 100644
--- a/net/ipv4/xfrm4_tunnel.c
+++ b/net/ipv4/xfrm4_tunnel.c
@@ -64,7 +64,7 @@
 	.priority	=	2,
 };
 
-#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
+#if IS_ENABLED(CONFIG_IPV6)
 static struct xfrm_tunnel xfrm64_tunnel_handler __read_mostly = {
 	.handler	=	xfrm_tunnel_rcv,
 	.err_handler	=	xfrm_tunnel_err,
@@ -84,7 +84,7 @@
 		xfrm_unregister_type(&ipip_type, AF_INET);
 		return -EAGAIN;
 	}
-#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
+#if IS_ENABLED(CONFIG_IPV6)
 	if (xfrm4_tunnel_register(&xfrm64_tunnel_handler, AF_INET6)) {
 		printk(KERN_INFO "ipip init: can't add xfrm handler for AF_INET6\n");
 		xfrm4_tunnel_deregister(&xfrm_tunnel_handler, AF_INET);
@@ -97,7 +97,7 @@
 
 static void __exit ipip_fini(void)
 {
-#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
+#if IS_ENABLED(CONFIG_IPV6)
 	if (xfrm4_tunnel_deregister(&xfrm64_tunnel_handler, AF_INET6))
 		printk(KERN_INFO "ipip close: can't remove xfrm handler for AF_INET6\n");
 #endif