memory: tegra20: Support interconnect framework

Now Internal and External Memory Controllers are memory interconnection
providers. This allows us to use interconnect API for tuning of memory
configuration. EMC driver now supports OPPs and DVFS.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Link: https://lore.kernel.org/r/20201104164923.21238-36-digetx@gmail.com


Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>