net: fec: Fixup EEE

The enabling/disabling of EEE in the MAC should happen as a result of
auto negotiation. So move the enable/disable into
fec_enet_adjust_link() which gets called by phylib when there is a
change in link status.

fec_enet_set_eee() now just stores away the LPI timer value.
Everything else is passed to phylib, so it can correctly setup the
PHY.

fec_enet_get_eee() relies on phylib doing most of the work,
the MAC driver just adds the LPI timer value.

Call phy_support_eee() if the quirk is present to indicate the MAC
actually supports EEE.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Tested-by: Oleksij Rempel <o.rempel@pengutronix.de> (On iMX8MP debix)
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Reviewed-by: Wei Fang <wei.fang@nxp.com>
Link: https://lore.kernel.org/r/20240302195306.3207716-8-o.rempel@pengutronix.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>