drm/i915: Use clamp_t() when limiting cur_delay

Make the cur_delay limiting code a bit less prone to typo errors
by using clamp_t().

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_irq.c

@@ -966,10 +966,8 @@ static void gen6_pm_rps_work(struct work_struct *work)
 	/* sysfs frequency interfaces may have snuck in while servicing the
 	 * interrupt
 	 */
-	if (new_delay < (int)dev_priv->rps.min_delay)
-		new_delay = dev_priv->rps.min_delay;
-	if (new_delay > (int)dev_priv->rps.max_delay)
-		new_delay = dev_priv->rps.max_delay;
+	new_delay = clamp_t(int, new_delay,
+			    dev_priv->rps.min_delay, dev_priv->rps.max_delay);
 	dev_priv->rps.last_adj = new_delay - dev_priv->rps.cur_delay;
 
 	if (IS_VALLEYVIEW(dev_priv->dev))