ARM: tegra: Enable PCIe controller on Beaver

PCIe lane 0 is connected to an onboard Gigabit Ethernet (RTL8168evl) and
lane 4 is routed to the board's miniPCIe slot.

Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>