netns: mib6 section fixlet

  LD      net/ipv6/ipv6.o
WARNING: net/ipv6/ipv6.o(.text+0xd8): Section mismatch in reference from the function inet6_net_init() to the function .init.text:ipv6_init_mibs()
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6/af_inet6.c

@@ -834,7 +834,7 @@ static void __net_exit ipv6_cleanup_mibs(struct net *net)
 	snmp_mib_free((void **)net->mib.icmpv6msg_statistics);
 }
 
-static int inet6_net_init(struct net *net)
+static int __net_init inet6_net_init(struct net *net)
 {
 	int err = 0;