ARM: tegra: add PCIe controller to Tegra186 SoC DT

ARM: tegra: add PCIe controller to Tegra186 SoC DT

The Tegra186 PCIe DT content is almost identical to previous chips, except
that the:

- There are 3 ports instead of 2.
- Some physical addresses have moved.
- PHY programming is handled by firmware, so CCPLEX DTs don't need to
  reference any PHY.
- The power domain is explicitly represented in DT. This change is
  mandatory for Tegra186 since standard power domain APIs are used, and
  should be made to the DT for older SoCs, although we get away without
  doing so since U-Boot currently uses custom APIs that hard-code power
  domain IDs.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Warren <twarren@nvidia.com>