ixgbe: Use C45 mdiobus accessors

When performing a C45 bus transaction, make use of the c45 variants of
the bus read/write helpers. The ability to pass a special register
value is being removed to clean up the mdio bus driver API.
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Michael Walle <michael@walle.cc>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/intel/ixgbe/ixgbe_main.c

@@ -8937,7 +8937,8 @@ ixgbe_mdio_read(struct net_device *netdev, int prtad, int devad, u16 addr)
 		int regnum = addr;
 
 		if (devad != MDIO_DEVAD_NONE)
-			regnum |= (devad << 16) | MII_ADDR_C45;
+			return mdiobus_c45_read(adapter->mii_bus, prtad,
+						devad, regnum);
 
 		return mdiobus_read(adapter->mii_bus, prtad, regnum);
 	}
@@ -8960,7 +8961,8 @@ static int ixgbe_mdio_write(struct net_device *netdev, int prtad, int devad,
 		int regnum = addr;
 
 		if (devad != MDIO_DEVAD_NONE)
-			regnum |= (devad << 16) | MII_ADDR_C45;
+			return mdiobus_c45_write(adapter->mii_bus, prtad, devad,
+						 regnum, value);
 
 		return mdiobus_write(adapter->mii_bus, prtad, regnum, value);
 	}