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/sctp/input.c b/net/sctp/input.c
index b7692aa..80f71af 100644
--- a/net/sctp/input.c
+++ b/net/sctp/input.c
@@ -105,7 +105,7 @@
 struct sctp_input_cb {
 	union {
 		struct inet_skb_parm	h4;
-#if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
+#if IS_ENABLED(CONFIG_IPV6)
 		struct inet6_skb_parm	h6;
 #endif
 	} header;