net: phylink: force link down on major_config failure

If we fail to configure the MAC or PCS according to the desired mode,
do not allow the network link to come up until we have successfully
configured the MAC and PCS. This improves phylink's behaviour when an
error occurs.

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://patch.msgid.link/E1twkqO-0006FI-Gm@rmk-PC.armlinux.org.uk


Signed-off-by: Jakub Kicinski <kuba@kernel.org>