net: phy: marvell: avoid configuring fiber page for SGMII-to-Copper

When in SGMII-to-Copper mode, the fiber page is used for the MAC facing
link, and does not require configuration of the fiber auto-negotiation
settings.  Avoid trying.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/phy/marvell.c

@@ -637,6 +637,10 @@ static int m88e1510_config_aneg(struct phy_device *phydev)
 	if (err < 0)
 		goto error;
 
+	/* Do not touch the fiber page if we're in copper->sgmii mode */
+	if (phydev->interface == PHY_INTERFACE_MODE_SGMII)
+		return 0;
+
 	/* Then the fiber link */
 	err = marvell_set_page(phydev, MII_MARVELL_FIBER_PAGE);
 	if (err < 0)