drivers/net: const-ify ethtool_ops declarations

Signed-off-by: Jeff Garzik <jeff@garzik.org>
diff --git a/drivers/net/spider_net_ethtool.c b/drivers/net/spider_net_ethtool.c
index 0220922..b0e65d0 100644
--- a/drivers/net/spider_net_ethtool.c
+++ b/drivers/net/spider_net_ethtool.c
@@ -142,7 +142,7 @@
 	ering->rx_pending = card->rx_desc;
 }
 
-struct ethtool_ops spider_net_ethtool_ops = {
+const struct ethtool_ops spider_net_ethtool_ops = {
 	.get_settings		= spider_net_ethtool_get_settings,
 	.get_drvinfo		= spider_net_ethtool_get_drvinfo,
 	.get_wol		= spider_net_ethtool_get_wol,