bridge: always declare tunnel functions

When CONFIG_BRIDGE_VLAN_FILTERING is disabled, two functions are still
defined but have no prototype or caller. This causes a W=1 warning for
the missing prototypes:

net/bridge/br_netlink_tunnel.c:29:6: error: no previous prototype for 'vlan_tunid_inrange' [-Werror=missing-prototypes]
net/bridge/br_netlink_tunnel.c:199:5: error: no previous prototype for 'br_vlan_tunnel_info' [-Werror=missing-prototypes]

The functions are already contitional on CONFIG_BRIDGE_VLAN_FILTERING,
and I coulnd't easily figure out the right set of #ifdefs, so just
move the declarations out of the #ifdef to avoid the warning,
at a small cost in code size over a more elaborate fix.

Fixes: 188c67dd1906 ("net: bridge: vlan options: add support for tunnel id dumping")
Fixes: 569da0822808 ("net: bridge: vlan options: add support for tunnel mapping set/del")
Signed-off-by: Arnd Bergmann <[e-mail]>
Acked-by: Nikolay Aleksandrov <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

net/bridge/br_private_tunnel.h

···
 int br_get_vlan_tunnel_info_size(struct net_bridge_vlan_group *vg);
 int br_fill_vlan_tunnel_info(struct sk_buff *skb,
 			     struct net_bridge_vlan_group *vg);
+bool vlan_tunid_inrange(const struct net_bridge_vlan *v_curr,
+			const struct net_bridge_vlan *v_last);
+int br_vlan_tunnel_info(const struct net_bridge_port *p, int cmd,
+			u16 vid, u32 tun_id, bool *changed);
 
 #ifdef CONFIG_BRIDGE_VLAN_FILTERING
 /* br_vlan_tunnel.c */
···
 				   struct net_bridge_vlan_group *vg);
 int br_handle_egress_vlan_tunnel(struct sk_buff *skb,
 				 struct net_bridge_vlan *vlan);
-bool vlan_tunid_inrange(const struct net_bridge_vlan *v_curr,
-			const struct net_bridge_vlan *v_last);
-int br_vlan_tunnel_info(const struct net_bridge_port *p, int cmd,
-			u16 vid, u32 tun_id, bool *changed);
 #else
 static inline int vlan_tunnel_init(struct net_bridge_vlan_group *vg)
 {