thermal: tegra: move tegra thermal files into tegra directory

Move Tegra soctherm driver to tegra directory, it's easy to maintain
and add more new function support for Tegra platforms.
This will also help to split soctherm driver into common parts and
chip specific data related parts.

Signed-off-by: Wei Ni <wni@nvidia.com>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>