net: phy: c45: migrate to genphy_c45_write_eee_adv()

Migrate from genphy_config_eee_advert() to genphy_c45_write_eee_adv().

It should work as before except write operation to the EEE adv registers
will be done only if some EEE abilities was detected.

If some driver will have a regression, related driver should provide own
.get_features callback. See micrel.c:ksz9477_get_features() as example.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>