net: rtl8169: Add support for RTL8168d/8111d

This chip is compatible with the existing driver, except that it uses
BAR2 instead of BAR1 for the I/O memory region. Using this patch I can
use the PCIe ethernet interface on the CompuLab Trimslice to boot from
the network.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Patch: 276477