PM-runtime: Fix 'jiffies' in comments after switch to hrtimers

PM-runtime now uses the hrtimers infrastructure for autosuspend, however
comments still reference 'jiffies'.

Fixes: 8234f6734c (PM-runtime: Switch autosuspend over to using hrtimers)
Signed-off-by: Ladislav Michl <ladis@linux-mips.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/base/power/runtime.c

@@ -121,7 +121,7 @@ static void pm_runtime_cancel_pending(struct device *dev)
  * Compute the autosuspend-delay expiration time based on the device's
  * power.last_busy time.  If the delay has already expired or is disabled
  * (negative) or the power.use_autosuspend flag isn't set, return 0.
- * Otherwise return the expiration time in jiffies (adjusted to be nonzero).
+ * Otherwise return the expiration time in nanoseconds (adjusted to be nonzero).
  *
  * This function may be called either with or without dev->power.lock held.
  * Either way it can be racy, since power.last_busy may be updated at any time.
@@ -905,7 +905,10 @@ static enum hrtimer_restart  pm_suspend_timer_fn(struct hrtimer *timer)
 	spin_lock_irqsave(&dev->power.lock, flags);
 
 	expires = dev->power.timer_expires;
-	/* If 'expire' is after 'jiffies' we've been called too early. */
+	/*
+	 * If 'expires' is after the current time, we've been called
+	 * too early.
+	 */
 	if (expires > 0 && expires < ktime_to_ns(ktime_get())) {
 		dev->power.timer_expires = 0;
 		rpm_suspend(dev, dev->power.timer_autosuspends ?