r8169: Don't disable ASPM in the driver

Enable or disable ASPM should be done in PCI core instead of in the
device driver.

Commit ba04c7c9

 ("r8169: disable ASPM") uses
pci_disable_link_state() to disable ASPM, but it's not the best way to
do it. If the device really wants to disable ASPM, we can use a quirk in
PCI core to prevent the PCI core from setting ASPM before probe.

Let's remove pci_disable_link_state() for now. Use PCI core quirks if
any regression happens.

Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>