arm64: tegra: Add NVIDIA Jetson TX1 support

The NVIDIA Jetson TX1 is a processor module that features a Tegra210 SoC
with 4 GiB of LPDDR4 RAM attached, a 32 GiB eMMC and other essentials.

It is typically connected to some I/O board (such as the P2597) that has
the connectors needed to hook it up to the outside world.

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