ARM: tegra: Enable PCIe on Cardhu

The PCIe bus on Cardhu is routed to the dock connector. An ethernet NIC
is available on the dock over the PCIe bus. Enable the PCIe controller
and the network device driver so that the device can boot over the
network.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Warren <twarren@nvidia.com>