net: phylink: make configuring clock-stop dependent on MAC support

We should not be configuring the PHYs clock-stop settings unless the
MAC supports phylink managed EEE. Make this dependent on MAC support.

This was noticed in a suspicious RCU usage report from the kernel
test robot (the suspicious RCU usage due to calling phy_detach()
remains unaddressed, but is triggered by the error this was
generating.)

Fixes: 03abf2a7 ("net: phylink: add EEE management")
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://patch.msgid.link/E1tgjNn-003q0w-Pw@rmk-PC.armlinux.org.uk


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