r8169: Align ASPM/CLKREQ setting function with vendor driver

There's a small delay after setting ASPM in vendor drivers, r8101 and
r8168.
In addition, those drivers enable ASPM before ClkReq, also change that
to align with vendor driver.

I haven't seen anything bad becasue of this, but I think it's better to
keep in sync with vendor driver.

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