r8169: don't activate ASPM in chip if OS can't control ASPM

Certain chip version / board combinations have massive problems if
ASPM is active. If BIOS enables ASPM and doesn't let OS control it,
then we may have a problem with the current code. Therefore check the
return code of pci_disable_link_state() and don't enable ASPM in the
network chip if OS can't control ASPM.

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