cpuidle: tegra: Squash Tegra114 driver into the common driver

Tegra20/30/114/124 SoCs have common idling states, thus there is no much
point in having separate drivers for a similar hardware. This patch moves
Tegra114/124 arch/ drivers into the common driver without any functional
changes. The CC6 state is kept disabled on Tegra114/124 because the core
Tegra PM code needs some more work in order to support that state.

Acked-by: Peter De Schrijver <pdeschrijver@nvidia.com>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Thierry Reding <treding@nvidia.com>