Replace the flag by a simple global boolean in the cpuidle.c.

That will allow to cleanup the rest of the code right after,
because the ops won't make sense.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Len Brown <len.brown@intel.com>