ARM: tegra: Add memory controller support for Tegra124

ARM: tegra: Add memory controller support for Tegra124

Add the memory controller and wire up the interrupt that is used to
report errors. Provide a reference to the memory controller clock and
mark the device as being an IOMMU by adding an #iommu-cells property.

Signed-off-by: Thierry Reding <treding@nvidia.com>