r8169: respect EEE user setting when restarting network

Currently, if network is re-started, we advertise all supported EEE
modes, thus potentially overriding a manual adjustment the user made
e.g. via ethtool. Be friendly to the user and preserve a manual
setting on network re-start.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>