ARM: tegra: Copy memory-region-names property

If multiple entries are present in the memory-region property, this new
memory-region-names property can be used to specify names for each of
them so that they can be more easily distinguished.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Warren <twarren@nvidia.com>