cpuidle: fix comment format

Fix comment format for the kernel doc script.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Merge branch 'pm-cpuidle-next' into linux-next

* pm-cpuidle-next:
  cpuidle: fix comment format