memory: tegra: Consolidate registers definition into common header

The Memory Controller registers definition is sparse and duplicated,
let's consolidate everything into a common place for consistency.

Acked-by: Peter De Schrijver <pdeschrijver@nvidia.com>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>