arm64: tegra: Enable HDMI on P2972-0000

Add the 5V HDMI regulator and hook up the VDD_1V0 and VDD_1V8HS supplies
from the PMIC to the display block. Also enable the display hub which is
responsible for instantiating the display controllers. Finally, enable
the third SOR that drives the TMDS signals to the HDMI connector.

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