openvswitch: fix a compilation error when CONFIG_INET is not setW!

Fix a openvswitch compilation error when CONFIG_INET is not set:

=====================================================
In file included from include/net/geneve.h:4:0,
from net/openvswitch/flow_netlink.c:45:
include/net/udp_tunnel.h: In function 'udp_tunnel_handle_offloads':
>> include/net/udp_tunnel.h:100:2: error: implicit declaration of function 'iptunnel_handle_offloads' [-Werror=implicit-function-declaration]
>> return iptunnel_handle_offloads(skb, udp_csum, type);
>> ^
>> >> include/net/udp_tunnel.h:100:2: warning: return makes pointer from integer without a cast
>> >> cc1: some warnings being treated as errors

=====================================================

Reported-by: kbuild test robot <[e-mail]>
Signed-off-by: Andy Zhou <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/net/Kconfig

···
 config VXLAN
        tristate "Virtual eXtensible Local Area Network (VXLAN)"
        depends on INET
-       select NET_IP_TUNNEL
        select NET_UDP_TUNNEL
        ---help---
 	  This allows one to create vxlan virtual interfaces that provide

include/net/geneve.h

···
 #ifndef __NET_GENEVE_H
 #define __NET_GENEVE_H  1
 
+#ifdef CONFIG_INET
 #include <net/udp_tunnel.h>
+#endif
 
-struct geneve_sock;
-
-typedef void (geneve_rcv_t)(struct geneve_sock *gs, struct sk_buff *skb);
-
-struct geneve_sock {
-	struct hlist_node	hlist;
-	geneve_rcv_t		*rcv;
-	void			*rcv_data;
-	struct work_struct	del_work;
-	struct socket		*sock;
-	struct rcu_head		rcu;
-	atomic_t		refcnt;
-	struct udp_offload	udp_offloads;
-};
 
 /* Geneve Header:
  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
···
 	struct geneve_opt options[];
 };
 
+#ifdef CONFIG_INET
+struct geneve_sock;
+
+typedef void (geneve_rcv_t)(struct geneve_sock *gs, struct sk_buff *skb);
+
+struct geneve_sock {
+	struct hlist_node	hlist;
+	geneve_rcv_t		*rcv;
+	void			*rcv_data;
+	struct work_struct	del_work;
+	struct socket		*sock;
+	struct rcu_head		rcu;
+	atomic_t		refcnt;
+	struct udp_offload	udp_offloads;
+};
+
 #define GENEVE_VER 0
 #define GENEVE_BASE_HLEN (sizeof(struct udphdr) + sizeof(struct genevehdr))
 
···
 		    __u8 ttl, __be16 df, __be16 src_port, __be16 dst_port,
 		    __be16 tun_flags, u8 vni[3], u8 opt_len, u8 *opt,
 		    bool xnet);
-#endif
+#endif /*ifdef CONFIG_INET */
+
+#endif /*ifdef__NET_GENEVE_H */

net/ipv4/Kconfig

···
 
 config NET_UDP_TUNNEL
 	tristate
+	select NET_IP_TUNNEL
 	default n
 
 config NET_FOU
···
 	  over UDP include tunnels (IPIP, GRE, SIT). By encapsulating in UDP
 	  network mechanisms and optimizations for UDP (such as ECMP
 	  and RSS) can be leveraged to provide better service.
+
+config GENEVE
+	tristate "Generic Network Virtualization Encapsulation (Geneve)"
+	depends on INET
+	select NET_UDP_TUNNEL
+	---help---
+	This allows one to create Geneve virtual interfaces that provide
+	Layer 2 Networks over Layer 3 Networks. Geneve is often used
+	to tunnel virtual network infrastructure in virtualized environments.
+	For more information see:
+	  http://tools.ietf.org/html/draft-gross-geneve-01
+
+	  To compile this driver as a module, choose M here: the module
+
 
 config INET_AH
 	tristate "IP: AH transformation"
···
 	scalability. Under small congestion windows, binary search
 	increase provides TCP friendliness.
 	See http://www.csc.ncsu.edu/faculty/rhee/export/bitcp/
-
-config GENEVE
-	tristate "Generic Network Virtualization Encapsulation (Geneve)"
-	depends on INET
-	select NET_IP_TUNNEL
-	select NET_UDP_TUNNEL
-	---help---
-	This allows one to create Geneve virtual interfaces that provide
-	Layer 2 Networks over Layer 3 Networks. Geneve is often used
-	to tunnel virtual network infrastructure in virtualized environments.
-	For more information see:
-	  http://tools.ietf.org/html/draft-gross-geneve-01
-
-	  To compile this driver as a module, choose M here: the module
 
 config TCP_CONG_CUBIC
 	tristate "CUBIC TCP"