drm/i915: Restrict plane loops to only operate on overlay planes (v2)

Ensure that existing driver loops over all planes do not change behavior
when we begin adding new types of planes (primary and cursor) to the DRM
plane list in future patches.

v2: Switch to using drm_for_each_legacy_plane()

Cc: Intel Graphics Development <[e-mail]>
Signed-off-by: Matt Roper <[e-mail]>

drivers/gpu/drm/i915/intel_display.c

···
 {
 	struct drm_device *dev = crtc->dev;
 	enum pipe pipe = to_intel_crtc(crtc)->pipe;
+	struct drm_plane *plane;
 	struct intel_plane *intel_plane;
 
-	list_for_each_entry(intel_plane, &dev->mode_config.plane_list, base.head)
+	drm_for_each_legacy_plane(plane, &dev->mode_config.plane_list) {
+		intel_plane = to_intel_plane(plane);
 		if (intel_plane->pipe == pipe)
 			intel_plane_restore(&intel_plane->base);
+	}
 }
 
 static void intel_disable_planes(struct drm_crtc *crtc)
 {
 	struct drm_device *dev = crtc->dev;
 	enum pipe pipe = to_intel_crtc(crtc)->pipe;
+	struct drm_plane *plane;
 	struct intel_plane *intel_plane;
 
-	list_for_each_entry(intel_plane, &dev->mode_config.plane_list, base.head)
+	drm_for_each_legacy_plane(plane, &dev->mode_config.plane_list) {
+		intel_plane = to_intel_plane(plane);
 		if (intel_plane->pipe == pipe)
 			intel_plane_disable(&intel_plane->base);
+	}
 }
 
 void hsw_enable_ips(struct intel_crtc *crtc)

drivers/gpu/drm/i915/intel_pm.c

···
 	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head)
 		config->num_pipes_active += intel_crtc_active(crtc);
 
-	list_for_each_entry(plane, &dev->mode_config.plane_list, head) {
+	drm_for_each_legacy_plane(plane, &dev->mode_config.plane_list) {
 		struct intel_plane *intel_plane = to_intel_plane(plane);
 
 		if (intel_plane->pipe == pipe)