soc/tegra: pmc: Enable core domain support for Tegra20 and Tegra30

All device drivers got runtime PM and OPP support. Flip the core domain
support status for Tegra20 and Tegra30 SoCs.

Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>