net: phy: constify netdev->dev_addr references

netdev->dev_addr will become a const soon(ish),
constify the local variables referring to it.
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/phy/dp83867.c

@@ -182,7 +182,7 @@ static int dp83867_set_wol(struct phy_device *phydev,
 {
 	struct net_device *ndev = phydev->attached_dev;
 	u16 val_rxcfg, val_micr;
-	u8 *mac;
+	const u8 *mac;
 
 	val_rxcfg = phy_read_mmd(phydev, DP83867_DEVADDR, DP83867_RXFCFG);
 	val_micr = phy_read(phydev, MII_DP83867_MICR);
@@ -193,7 +193,7 @@ static int dp83867_set_wol(struct phy_device *phydev,
 		val_micr |= MII_DP83867_MICR_WOL_INT_EN;
 
 		if (wol->wolopts & WAKE_MAGIC) {
-			mac = (u8 *)ndev->dev_addr;
+			mac = (const u8 *)ndev->dev_addr;
 
 			if (!is_valid_ether_addr(mac))
 				return -EINVAL;

drivers/net/phy/dp83869.c

@@ -246,7 +246,7 @@ static int dp83869_set_wol(struct phy_device *phydev,
 {
 	struct net_device *ndev = phydev->attached_dev;
 	int val_rxcfg, val_micr;
-	u8 *mac;
+	const u8 *mac;
 	int ret;
 
 	val_rxcfg = phy_read_mmd(phydev, DP83869_DEVADDR, DP83869_RXFCFG);
@@ -264,7 +264,7 @@ static int dp83869_set_wol(struct phy_device *phydev,
 
 		if (wol->wolopts & WAKE_MAGIC ||
 		    wol->wolopts & WAKE_MAGICSECURE) {
-			mac = (u8 *)ndev->dev_addr;
+			mac = (const u8 *)ndev->dev_addr;
 
 			if (!is_valid_ether_addr(mac))
 				return -EINVAL;