drm/i915: Add .atomic_{get, set}_property() entrypoints to planes

When we flip on the DRIVER_ATOMIC bit, the DRM core will start calling
this entrypoint to set and lookup driver-specific plane property values,
rather than maintaining a shadow copy in object->properties.

Note that although we add these functions to the plane vtable, they will
not yet be called.  Future patches that switch our .set_property()
handler and/or enable full atomic functionality are required before
these code paths will be executed.

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 4edf771..3d65e8b 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -945,6 +945,14 @@
 			   struct drm_framebuffer *fb);
 void intel_cleanup_plane_fb(struct drm_plane *plane,
 			    struct drm_framebuffer *fb);
+int intel_plane_atomic_get_property(struct drm_plane *plane,
+				    const struct drm_plane_state *state,
+				    struct drm_property *property,
+				    uint64_t *val);
+int intel_plane_atomic_set_property(struct drm_plane *plane,
+				    struct drm_plane_state *state,
+				    struct drm_property *property,
+				    uint64_t val);
 
 /* shared dpll functions */
 struct intel_shared_dpll *intel_crtc_to_shared_dpll(struct intel_crtc *crtc);