net: netsec: fix error handling in netsec_register_mdio()

net: netsec: fix error handling in netsec_register_mdio()

If phy_device_register() fails, phy_device_free() need be called to
put refcount, so memory of phy device and device name can be freed
in callback function.

If get_phy_device() fails, mdiobus_unregister() need be called,
or it will cause warning in mdiobus_free() and kobject is leaked.

Fixes: 0d326cdbc883 ("net: socionext: Add Synquacer NetSec driver")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Link: https://lore.kernel.org/r/20221019064104.3228892-1-yangyingliang@huawei.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>