memory: tegra: Make per-SoC setup more generic

The current per-SoC setup code runs at a fairly arbitrary point during
probe, thereby making it less flexible for other SoC generations. Move
the call around slightly (after only the very basic, common setup that
applies to all SoC generations has been performed), which will allow
it to be used for other implementations.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Link: https://lore.kernel.org/r/20210602163302.120041-6-thierry.reding@gmail.com
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>