drm/i915: Replace call to commit_planes_on_crtc with internal update, v2.

drm_atomic_helper_commit_planes_on_crtc calls begin_commit,
then plane_update hooks, then flush_commit. Because we keep our own
visibility tracking through plane_state->visible there's no need to
rely on the atomic hooks for this.

By explicitly writing our own helper, we can update visible planes
as needed, which is useful to make NV12 support work as intended.

Changes since v1:
- Reword commit message. (Matt Roper)
- Rename to intel_update_planes_on_crtc(). (Matt)

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180920102711.4184-6-maarten.lankhorst@linux.intel.com
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 521d6aa..0770772 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -2186,6 +2186,10 @@ struct drm_plane_state *intel_plane_duplicate_state(struct drm_plane *plane);
 void intel_plane_destroy_state(struct drm_plane *plane,
 			       struct drm_plane_state *state);
 extern const struct drm_plane_helper_funcs intel_plane_helper_funcs;
+void intel_update_planes_on_crtc(struct intel_atomic_state *old_state,
+				 struct intel_crtc *crtc,
+				 struct intel_crtc_state *old_crtc_state,
+				 struct intel_crtc_state *new_crtc_state);
 int intel_plane_atomic_check_with_state(const struct intel_crtc_state *old_crtc_state,
 					struct intel_crtc_state *crtc_state,
 					const struct intel_plane_state *old_plane_state,