r8169: enable ASPM on RTL8168E-VL

Let's enable ASPM also on the RTL8168E-VL (chip version 34).
Works fine on my Zotac Mini PC with this chip. Temperature when
being idle is significantly lower than before due to reaching
deeper PC states.

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