arm64: tegra: Add display support on Tegra194

Tegra194 contains a display architecture very similar to that found on
the Tegra186. One notable exception is that DSI is no longer a supported
output. Instead there are four display controllers and four SORs (with a
DPAUX associated to each of them) that can drive HDMI or DP.

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