net: make ethtool_ops const

Auditing all usage of ethtool_ops found several drivers that
are not declaring the struct const when it should be.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ethernet/micrel/ksz884x.c b/drivers/net/ethernet/micrel/ksz884x.c
index a718865..6ed09a8 100644
--- a/drivers/net/ethernet/micrel/ksz884x.c
+++ b/drivers/net/ethernet/micrel/ksz884x.c
@@ -6607,7 +6607,7 @@
 	return 0;
 }
 
-static struct ethtool_ops netdev_ethtool_ops = {
+static const struct ethtool_ops netdev_ethtool_ops = {
 	.get_settings		= netdev_get_settings,
 	.set_settings		= netdev_set_settings,
 	.nway_reset		= netdev_nway_reset,