ip_tunnel: Call ip_tunnel_core_init() from inet_init()

Convert the module_init() to a invocation from inet_init() since
ip_tunnel_core is part of the INET built-in.

Fixes: 3093fbe7ff ("route: Per route IP tunnel metadata via lightweight tunnel")
Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/af_inet.c

@@ -112,6 +112,7 @@
 #include <net/raw.h>
 #include <net/icmp.h>
 #include <net/inet_common.h>
+#include <net/ip_tunnels.h>
 #include <net/xfrm.h>
 #include <net/net_namespace.h>
 #include <net/secure_seq.h>
@@ -1780,6 +1781,8 @@ static int __init inet_init(void)
 
 	dev_add_pack(&ip_packet_type);
 
+	ip_tunnel_core_init();
+
 	rc = 0;
 out:
 	return rc;