net: constify VFTs

Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/pppol2tp.c b/drivers/net/pppol2tp.c
index f1a9467..635dd5f 100644
--- a/drivers/net/pppol2tp.c
+++ b/drivers/net/pppol2tp.c
@@ -2517,7 +2517,7 @@
 	return 0;
 }
 
-static struct seq_operations pppol2tp_seq_ops = {
+static const struct seq_operations pppol2tp_seq_ops = {
 	.start		= pppol2tp_seq_start,
 	.next		= pppol2tp_seq_next,
 	.stop		= pppol2tp_seq_stop,
@@ -2565,7 +2565,7 @@
 	return seq_release(inode, file);
 }
 
-static struct file_operations pppol2tp_proc_fops = {
+static const struct file_operations pppol2tp_proc_fops = {
 	.owner		= THIS_MODULE,
 	.open		= pppol2tp_proc_open,
 	.read		= seq_read,