arm64: tegra: Rename top-level clocks

Clocks defined at the top level in device tree are no longer part of a
simple bus and therefore don't have a reg property. Nodes without a reg
property shouldn't have a unit-address either, so drop the unit address
from the node names. To ensure nodes aren't duplicated (in which case
they would end up merged in the final DTB), append the name of the clock
to the node name.

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