soc/tegra: fuse: Implement nvmem device

The nvmem framework provides a generic infrastructure and API to access
the type of information stored in fuses such as the Tegra FUSE block.

Implement an nvmem device that can be used to access the information in
a more generic way to decouple consumers from the custom Tegra API and
to add a more formal way of creating the dependency between the FUSE
device and the consumers.

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