memory: tegra: Fix missed registers values latching

Some of Memory Controller registers are shadowed and require latching in
order to copy assembly state into the active, MC_EMEM_ARB_CFG is one of
these registers.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>