netfilter: conntrack: wrap two inline functions in config checks.

nf_conntrack_synproxy.h contains three inline functions.  The contents
of two of them are wrapped in CONFIG_NETFILTER_SYNPROXY checks and just
return NULL if it is not enabled.  The third does nothing if they return
NULL, so wrap its contents as well.

nf_ct_timeout_data is only called if CONFIG_NETFILTER_TIMEOUT is
enabled.  Wrap its contents in a CONFIG_NETFILTER_TIMEOUT check like the
other inline functions in nf_conntrack_timeout.h.
Signed-off-by: Jeremy Sowden <jeremy@azazel.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

include/net/netfilter/nf_conntrack_synproxy.h

@@ -32,6 +32,7 @@ static inline struct nf_conn_synproxy *nfct_synproxy_ext_add(struct nf_conn *ct)
 static inline bool nf_ct_add_synproxy(struct nf_conn *ct,
 				      const struct nf_conn *tmpl)
 {
+#if IS_ENABLED(CONFIG_NETFILTER_SYNPROXY)
 	if (tmpl && nfct_synproxy(tmpl)) {
 		if (!nfct_seqadj_ext_add(ct))
 			return false;
@@ -39,6 +40,7 @@ static inline bool nf_ct_add_synproxy(struct nf_conn *ct,
 		if (!nfct_synproxy_ext_add(ct))
 			return false;
 	}
+#endif
 
 	return true;
 }

include/net/netfilter/nf_conntrack_timeout.h

@@ -32,6 +32,7 @@ struct nf_conn_timeout {
 static inline unsigned int *
 nf_ct_timeout_data(const struct nf_conn_timeout *t)
 {
+#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
 	struct nf_ct_timeout *timeout;
 
 	timeout = rcu_dereference(t->timeout);
@@ -39,6 +40,9 @@ nf_ct_timeout_data(const struct nf_conn_timeout *t)
 		return NULL;
 
 	return (unsigned int *)timeout->data;
+#else
+	return NULL;
+#endif
 }
 
 static inline