net: phylink: ensure PHY momentary link-fails are handled

Normally, phylib won't notify changes in quick succession. However, as
a result of commit 3e43b903 ("net: phy: Immediately call
adjust_link if only tx_lpi_enabled changes") this is no longer true -
it is now possible that phy_link_down() and phy_link_up() will both
complete before phylink's resolver has run, which means it'll miss that
pl->phy_state.link momentarily became false.

Rename "mac_link_dropped" to be more generic "link_failed" since it will
cover more than the MAC/PCS end of the link failing, and arrange to set
this in phylink_phy_change() if we notice that the PHY reports that the
link is down.

This will ensure that we capture an EEE reconfiguration event.

Fixes: 3e43b903 ("net: phy: Immediately call adjust_link if only tx_lpi_enabled changes")
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Oleksij Rempel <o.rempel@pengutronix.de>
Link: https://patch.msgid.link/E1tAtcW-002RBS-LB@rmk-PC.armlinux.org.uk


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