net: phy: mscc: fix a possible double unlock

On vsc8584_ptp_init failure we jump to the 'err' label, which unlocks
the MDIO bus lock. But vsc8584_ptp_init isn't called with the MDIO bus
lock taken, which could result in a double unlock. Fix this.

Fixes: ab2bf933 ("net: phy: mscc: 1588 block initialization")
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Antoine Tenart <antoine.tenart@bootlin.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/phy/mscc/mscc_main.c

@@ -1436,7 +1436,7 @@ static int vsc8584_config_init(struct phy_device *phydev)
 
 	ret = vsc8584_ptp_init(phydev);
 	if (ret)
-		goto err;
+		return ret;
 
 	phy_write(phydev, MSCC_EXT_PAGE_ACCESS, MSCC_PHY_PAGE_STANDARD);