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/bridge/br_private.h b/net/bridge/br_private.h
index 8996908..57dcd14 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -56,7 +56,7 @@
 {
 	union {
 		__be32	ip4;
-#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
+#if IS_ENABLED(CONFIG_IPV6)
 		struct in6_addr ip6;
 #endif
 	} u;