arm64: tegra: Support Jetson Orin NX

This adds a device tree for the Jetson Orin NX module, which is Jetson
AGX Orin's little sibling with 6 or 8 ARM Cortex-A78AE cores, an Ampere
GPU (1024 GPU and 32 tensor cores) and a number of accelerators for
machine learning, image processing and more.

The Jetson Orin NX comes with either 8 or 16 GiB of 128-bit LPDDR5 and
supports NVME for mass storage.

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