igb: constify e1000_phy_operations structure

This e1000_phy_operations structure is never modified, so declare it as
const.  Other structures of this type are already const.

Done with the help of Coccinelle.
Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/igb/e1000_82575.c

@@ -2920,7 +2920,7 @@ static struct e1000_mac_operations e1000_mac_ops_82575 = {
 #endif
 };
 
-static struct e1000_phy_operations e1000_phy_ops_82575 = {
+static const struct e1000_phy_operations e1000_phy_ops_82575 = {
 	.acquire              = igb_acquire_phy_82575,
 	.get_cfg_done         = igb_get_cfg_done_82575,
 	.release              = igb_release_phy_82575,

drivers/net/ethernet/intel/igb/e1000_hw.h

@@ -372,7 +372,7 @@ struct e1000_thermal_sensor_data {
 struct e1000_info {
 	s32 (*get_invariants)(struct e1000_hw *);
 	struct e1000_mac_operations *mac_ops;
-	struct e1000_phy_operations *phy_ops;
+	const struct e1000_phy_operations *phy_ops;
 	struct e1000_nvm_operations *nvm_ops;
 };