net: don't declare IPv6 non-local bind helper if CONFIG_IPV6 undefined

Fixes: 83ba4645152d ("net: add helpers checking if socket can be bound to nonlocal address")
Signed-off-by: Vincent Bernat <vincent@bernat.im>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/ipv6.h

@@ -766,13 +766,6 @@ static inline int ip6_sk_dst_hoplimit(struct ipv6_pinfo *np, struct flowi6 *fl6,
 	return hlimit;
 }
 
-static inline bool ipv6_can_nonlocal_bind(struct net *net,
-					  struct inet_sock *inet)
-{
-	return net->ipv6.sysctl.ip_nonlocal_bind ||
-		inet->freebind || inet->transparent;
-}
-
 /* copy IPv6 saddr & daddr to flow_keys, possibly using 64bit load/store
  * Equivalent to :	flow->v6addrs.src = iph->saddr;
  *			flow->v6addrs.dst = iph->daddr;
@@ -789,6 +782,13 @@ static inline void iph_to_flow_copy_v6addrs(struct flow_keys *flow,
 
 #if IS_ENABLED(CONFIG_IPV6)
 
+static inline bool ipv6_can_nonlocal_bind(struct net *net,
+					  struct inet_sock *inet)
+{
+	return net->ipv6.sysctl.ip_nonlocal_bind ||
+		inet->freebind || inet->transparent;
+}
+
 /* Sysctl settings for net ipv6.auto_flowlabels */
 #define IP6_AUTO_FLOW_LABEL_OFF		0
 #define IP6_AUTO_FLOW_LABEL_OPTOUT	1