netfilter: use IS_ENABLED() macro

replace:
 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
with
 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)

replace:
 #if !defined(CONFIG_NF_NAT) && !defined(CONFIG_NF_NAT_MODULE)
with
 #if !IS_ENABLED(CONFIG_NF_NAT)

replace:
 #if !defined(CONFIG_NF_CONNTRACK) && !defined(CONFIG_NF_CONNTRACK_MODULE)
with
 #if !IS_ENABLED(CONFIG_NF_CONNTRACK)

And add missing:
 IS_ENABLED(CONFIG_NF_CT_NETLINK)

in net/ipv{4,6}/netfilter/nf_nat_l3proto_ipv{4,6}.c

Signed-off-by: Duan Jiong <duanj.fnst@cn.fujitsu.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
diff --git a/net/netfilter/nf_nat_proto_udp.c b/net/netfilter/nf_nat_proto_udp.c
index 7df613f..b0ede2f 100644
--- a/net/netfilter/nf_nat_proto_udp.c
+++ b/net/netfilter/nf_nat_proto_udp.c
@@ -70,7 +70,7 @@
 	.manip_pkt		= udp_manip_pkt,
 	.in_range		= nf_nat_l4proto_in_range,
 	.unique_tuple		= udp_unique_tuple,
-#if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
+#if IS_ENABLED(CONFIG_NF_CT_NETLINK)
 	.nlattr_to_range	= nf_nat_l4proto_nlattr_to_range,
 #endif
 };