r8169: fix runtime suspend

When runtime-suspending we configure WoL w/o touching saved_wolopts.
If saved_wolopts == 0 we would power down the PHY in this case what's
wrong. Therefore we have to check the actual chip WoL settings here.

Fixes: 433f9d0d

 ("r8169: improve saved_wolopts handling")
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>