ARM: tegra: Enable CPUFreq support for Tegra124 Chromebooks

Add the device-tree DFLL clock node and CPU regulator phandle for
Tegra124 Chromebooks to enable CPUFreq support on these boards.

Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Reviewed-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>