drm/i915: Use for_each_crtc() when iterating through the CRTCs

Patch done using the following semantic patch (thanks Daniel for the
help!)

  @@
  iterator name list_for_each_entry;
  iterator name for_each_crtc;
  struct drm_crtc * crtc;
  struct drm_device * dev;
  @@
  -list_for_each_entry(crtc,&dev->mode_config.crtc_list, head) {
  +for_each_crtc(dev,crtc) {
  	...
  }

Followed by a couple of fixups by hand (that spatch doesn't match the
cases where list_for_each_entry() is not followed by a set of '{', '}',
but I couldn't figure out a way to leave the '{' out of the iterator
match).

Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_drv.c

@@ -486,7 +486,7 @@ static int i915_drm_freeze(struct drm_device *dev)
 		 * for _thaw.
 		 */
 		mutex_lock(&dev->mode_config.mutex);
-		list_for_each_entry(crtc, &dev->mode_config.crtc_list, head)
+		for_each_crtc(dev, crtc)
 			dev_priv->display.crtc_disable(crtc);
 		mutex_unlock(&dev->mode_config.mutex);