drm/exynos: 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: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
diff --git a/drivers/gpu/drm/exynos/exynos_drm_crtc.c b/drivers/gpu/drm/exynos/exynos_drm_crtc.c
index 9cc92ae..5c9afa1 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_crtc.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_crtc.c
@@ -190,7 +190,7 @@
 
 	exynos_drm_crtc_dpms(crtc, DRM_MODE_DPMS_OFF);
 
-	list_for_each_entry(plane, &crtc->dev->mode_config.plane_list, head) {
+	drm_for_each_legacy_plane(plane, &crtc->dev->mode_config.plane_list) {
 		if (plane->crtc != crtc)
 			continue;
 
diff --git a/drivers/gpu/drm/exynos/exynos_drm_encoder.c b/drivers/gpu/drm/exynos/exynos_drm_encoder.c
index 835c0f1..7e282e3 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_encoder.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_encoder.c
@@ -101,7 +101,7 @@
 	exynos_drm_encoder_dpms(encoder, DRM_MODE_DPMS_OFF);
 
 	/* all planes connected to this encoder should be also disabled. */
-	list_for_each_entry(plane, &dev->mode_config.plane_list, head) {
+	drm_for_each_legacy_plane(plane, &dev->mode_config.plane_list) {
 		if (plane->crtc == encoder->crtc)
 			plane->funcs->disable_plane(plane);
 	}