ARM: tegra2: cpuidle: change driver initialization

Initialize the idle states directly in the driver structure.

That prevents extra structure declaration and memcpy at init time.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Reviewed-by: Joseph Lo <josephl@nvidia.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>