cpuidle: remove vestage definition of cpuidle_state_usage.driver_data

This field is no longer used.

Signed-off-by: Len Brown <len.brown@intel.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Merge branches 'idle-remove-statedata', 'pm_idle' and 'turbostat' into release
Merge branch 'idle-misc' into release

Conflicts: (remove/update resolves to remove)
	arch/x86/kernel/process.c

Signed-off-by: Len Brown <len.brown@intel.com>