net: sun8i-emac: Bail out on PHY error

net: sun8i-emac: Bail out on PHY error

When phy_startup() returns with an error, because there is no link or
the user interrupted the process, we shall stop the _start() routine
and return with an error, instead of proceeding anyway.

This fixes pointless operations when there is no Ethernet cable
connected, for instance.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Acked-by: Maxime Ripard <mripard@kernel.org>
Tested-by: Amit Singh Tomar <amittomer25@gmail.com> # Pine64+
Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>