drivers/net: const-ify ethtool_ops declarations

Signed-off-by: Jeff Garzik <jeff@garzik.org>
diff --git a/drivers/net/tulip/de2104x.c b/drivers/net/tulip/de2104x.c
index 17a2eba..e1b48bd 100644
--- a/drivers/net/tulip/de2104x.c
+++ b/drivers/net/tulip/de2104x.c
@@ -1670,7 +1670,7 @@
 	spin_unlock_irq(&de->lock);
 }
 
-static struct ethtool_ops de_ethtool_ops = {
+static const struct ethtool_ops de_ethtool_ops = {
 	.get_link		= ethtool_op_get_link,
 	.get_tx_csum		= ethtool_op_get_tx_csum,
 	.get_sg			= ethtool_op_get_sg,