l2tp: fix possible oops on l2tp_eth module unload

A struct used in the l2tp_eth driver for registering network namespace
ops was incorrectly marked as __net_initdata, leading to oops when
module unloaded.

BUG: unable to handle kernel paging request at ffffffffa00ec098
IP: [<ffffffff8123dbd8>] ops_exit_list+0x7/0x4b
PGD 142d067 PUD 1431063 PMD 195da8067 PTE 0
Oops: 0000 [#1] SMP 
last sysfs file: /sys/module/l2tp_eth/refcnt
Call Trace:
 [<ffffffff8123dc94>] ? unregister_pernet_operations+0x32/0x93
 [<ffffffff8123dd20>] ? unregister_pernet_device+0x2b/0x38
 [<ffffffff81068b6e>] ? sys_delete_module+0x1b8/0x222
 [<ffffffff810c7300>] ? do_munmap+0x254/0x318
 [<ffffffff812c64e5>] ? page_fault+0x25/0x30
 [<ffffffff812c6952>] ? system_call_fastpath+0x16/0x1b
Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/l2tp/l2tp_eth.c

@@ -283,7 +283,7 @@ static __net_init int l2tp_eth_init_net(struct net *net)
 	return 0;
 }
 
-static __net_initdata struct pernet_operations l2tp_eth_net_ops = {
+static struct pernet_operations l2tp_eth_net_ops = {
 	.init = l2tp_eth_init_net,
 	.id   = &l2tp_eth_net_id,
 	.size = sizeof(struct l2tp_eth_net),