ACPI / idle: remove usage of the statedata

Len Brown sent a patch to remove this field in the intel_idle driver.
The other user of this field is the davinci cpuidle driver and a
patch has been sent to remove the usage of it.

This patch removes the last user of this field.

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