r8169: simplify RTL8169 PHY initialization

PCI_LATENCY_TIMER is ignored on PCIe, therefore we have to do this
for the PCI chips (version <= 06) only. Also we can move setting
PCI_CACHE_LINE_SIZE.

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