net: 3c59x: constify eisa_device_id

eisa_device_id are not supposed to change at runtime. All functions
working with eisa_device_id provided by <linux/eisa.h> work with
const eisa_device_id. So mark the non-const structs as const.
Signed-off-by: NArvind Yadav <arvind.yadav.cs@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/3com/3c59x.c

@@ -900,7 +900,7 @@ static const struct dev_pm_ops vortex_pm_ops = {
 #endif /* !CONFIG_PM */
 
 #ifdef CONFIG_EISA
-static struct eisa_device_id vortex_eisa_ids[] = {
+static const struct eisa_device_id vortex_eisa_ids[] = {
 	{ "TCM5920", CH_3C592 },
 	{ "TCM5970", CH_3C597 },
 	{ "" }