r8169: avoid link-up interrupt issue on RTL8106e if user enables ASPM

It has been reported that on RTL8106e the link-up interrupt may be
significantly delayed if the user enables ASPM L1. Per default ASPM
is disabled. The change leaves L1 enabled on the PCIe link (thus still
allowing to reach higher package power saving states), but the
NIC won't actively trigger it.

Reported-by: Koba Ko <koba.ko@canonical.com>
Tested-by: Koba Ko <koba.ko@canonical.com>
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>