arm64: tegra: Add device tree for the Tegra194 P2972-0000 board

Add device tree files for the Tegra194 P2972-0000 development board.
The board consists of the P2888 compute module and the P2822 baseboard.

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