memory: tegra: Unify drivers

The Tegra210 (and earlier) driver now supports all the functionality
that the Tegra186 (and later) driver does, so they can be unified.

Note that previously the Tegra186 (and later) driver could be unloaded,
even if that was perhaps not very useful. Older chips don't support that
yet, but once they do this code can be reenabled.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Link: https://lore.kernel.org/r/20210602163302.120041-11-thierry.reding@gmail.com


Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>