soc/tegra: Add Tegra186 support

The Tegra186 features a combination of Denver and Cortex-A57 CPU cores
and a GPU based on the Pascal architecture. It contains an ADSP with a
Cortex-A9 CPU used for audio processing, hardware video encoders and
decoders with multi-format support, ISP for image capture processing
and BPMP for power management.

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