arm64: tegra: Add P2U and PCIe controller nodes to Tegra194 DT

Add P2U (PIPE to UPHY) and PCIe controller nodes to device tree.
The Tegra194 SoC contains six PCIe controllers and twenty P2U instances
grouped into two different PHY bricks namely High-Speed IO (HSIO-12 P2Us)
and NVIDIA High Speed (NVHS-8 P2Us) respectively.

Signed-off-by: Vidya Sagar <vidyas@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>