This is caused by the mdiobus being unregistered/free'd
and the code in phy_detach() attempting to manipulate mdio
related structures from unregister_netdev() calling close()
To fix this, we delay the mdiobus teardown until after
the netdev is deregistered.
Reported-by: Matt Sealey <matt.sealey@arm.com> Signed-off-by: Jeremy Linton <jeremy.linton@arm.com> Reviewed-by: Andrew Lunn <andrew@lunn.ch> Signed-off-by: David S. Miller <davem@davemloft.net>