drm/i915: Consolidate plane handler vtables

All of the previous refactoring/consolidation of plane code has resulted
in intel_primary_plane_funcs, intel_cursor_plane_funcs, and
intel_sprite_plane_funcs being identical.  Replace all of these with a
single 'intel_plane_funcs' vtable for simplicity.

Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Ander Conselvan de Oliveira <conselvan2@gmail.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 a9c00bd..4edf771 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -890,6 +890,7 @@
 void i915_audio_component_cleanup(struct drm_i915_private *dev_priv);
 
 /* intel_display.c */
+extern const struct drm_plane_funcs intel_plane_funcs;
 bool intel_has_pending_fb_unpin(struct drm_device *dev);
 int intel_pch_rawclk(struct drm_device *dev);
 void intel_mark_busy(struct drm_device *dev);