soc/tegra: pmc: Rename 3d power domains

Device-tree schema doesn't allow domain name to start with a number.
We don't use 3d domain yet in device-trees, so rename it to the name
used by Tegra TRMs: TD, TD2.

Reported-by: David Heidelberg <david@ixit.cz>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>