netfilter: nf_conntrack: elegantly simplify nf_ct_exp_net()

Remove #ifdef at nf_ct_exp_net() by using nf_ct_net().
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>

include/net/netfilter/nf_conntrack_expect.h

@@ -56,11 +56,7 @@ struct nf_conntrack_expect {
 
 static inline struct net *nf_ct_exp_net(struct nf_conntrack_expect *exp)
 {
-#ifdef CONFIG_NET_NS
-	return exp->master->ct_net;	/* by definition */
-#else
-	return &init_net;
-#endif
+	return nf_ct_net(exp->master);
 }
 
 struct nf_conntrack_expect_policy {