net: ethernet: arc: Don't free Rockchip resources before disconnect from phy

Free resources before being disconnected from phy and calling core driver is
wrong and should not happen. It avoids a delay of 4-5s caused by the timeout of
phy_disconnect().

Signed-off-by: Romain Perier <romain.perier@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>