drm/i915: Split plane updates of crtc->atomic into a helper, v2.

This makes it easier to verify that no changes are done when
calling this from crtc instead.

Changes since v1:
 - Make intel_wm_need_update static and always check it.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Tested-by(IVB): Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 2436af9..198cb20 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -1067,6 +1067,8 @@
 				    struct drm_plane_state *state,
 				    struct drm_property *property,
 				    uint64_t val);
+int intel_plane_atomic_calc_changes(struct drm_crtc_state *crtc_state,
+				    struct drm_plane_state *plane_state);
 
 unsigned int
 intel_tile_height(struct drm_device *dev, uint32_t pixel_format,
@@ -1081,9 +1083,6 @@
 void intel_create_rotation_property(struct drm_device *dev,
 					struct intel_plane *plane);
 
-bool intel_wm_need_update(struct drm_plane *plane,
-			  struct drm_plane_state *state);
-
 /* shared dpll functions */
 struct intel_shared_dpll *intel_crtc_to_shared_dpll(struct intel_crtc *crtc);
 void assert_shared_dpll(struct drm_i915_private *dev_priv,
@@ -1148,9 +1147,6 @@
 void intel_crtc_wait_for_pending_flips(struct drm_crtc *crtc);
 void intel_modeset_preclose(struct drm_device *dev, struct drm_file *file);
 void skl_detach_scalers(struct intel_crtc *intel_crtc);
-int skl_update_scaler_plane(struct intel_crtc_state *crtc_state,
-			    struct intel_plane *intel_plane,
-			    struct intel_plane_state *plane_state);
 
 int skl_update_scaler_crtc(struct intel_crtc_state *crtc_state, int force_detach);
 int skl_max_scale(struct intel_crtc *crtc, struct intel_crtc_state *crtc_state);