drivers/net: const-ify ethtool_ops declarations

Signed-off-by: Jeff Garzik <jeff@garzik.org>
diff --git a/drivers/net/tulip/tulip_core.c b/drivers/net/tulip/tulip_core.c
index 0a339df..831919a 100644
--- a/drivers/net/tulip/tulip_core.c
+++ b/drivers/net/tulip/tulip_core.c
@@ -837,7 +837,7 @@
 	strcpy(info->bus_info, pci_name(np->pdev));
 }
 
-static struct ethtool_ops ops = {
+static const struct ethtool_ops ops = {
 	.get_drvinfo = tulip_get_drvinfo
 };