cpuidle: intel_idle: Update intel_idle() kerneldoc comment

Commit bf9282d ("cpuidle: Make CPUIDLE_FLAG_TLB_FLUSHED generic")
moved the leave_mm() call away from intel_idle(), but it didn't update
its kerneldoc comment accordingly, so do that now.

Fixes: bf9282d ("cpuidle: Make CPUIDLE_FLAG_TLB_FLUSHED generic")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/idle/intel_idle.c

@@ -122,9 +122,6 @@ static unsigned int mwait_substates __initdata;
  * If the local APIC timer is not known to be reliable in the target idle state,
  * enable one-shot tick broadcasting for the target CPU before executing MWAIT.
  *
- * Optionally call leave_mm() for the target CPU upfront to avoid wakeups due to
- * flushing user TLBs.
- *
  * Must be called under local_irq_disable().
  */
 static __cpuidle int intel_idle(struct cpuidle_device *dev,