net: stmmac: report PCS link changes to phylink

net: stmmac: report PCS link changes to phylink

Report PCS link changes to phylink, which will allow phylink's inband
support to respoind to link events once the PCS is appropriately
configured.

An expected behavioural change is that should the PCS report that its
link has failed, but phylink is operating in outband mode and the PHY
reports that link is up, this event will cause the netdev's link to
momentarily drop, making the event more noticable, rather than just
producing a "stmmac_pcs: Link Down" message.

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://patch.msgid.link/E1vevI1-00000002Yp8-3cM3@rmk-PC.armlinux.org.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>