net: mdio: octeon: Fix some double free issues

'bus->mii_bus' has been allocated with 'devm_mdiobus_alloc_size()' in the
probe function. So it must not be freed explicitly or there will be a
double free.

Remove the incorrect 'mdiobus_free' in the error handling path of the
probe function and in remove function.

Suggested-By: Andrew Lunn <andrew@lunn.ch>
Fixes: 35d2aeac ("phy: mdio-octeon: Use devm_mdiobus_alloc_size()")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: Russell King <rmk+kernel@armlinux.org.uk>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>