drm/i915: Add plumbing for digital connector state, v3.

Some atomic properties are common between the various kinds of
connectors, for example a lot of them use panel fitting mode.
It makes sense to put a lot of it in a common place, so each
connector can use it while they're being converted.

Implement the properties required for the connectors:
- scaling mode property
- force audio property
- broadcast rgb
- aspect ratio

While at it, make clear that intel_digital_connector_atomic_get_property
is a hack that has to be removed when all connector properties
are converted to atomic.

Changes since v1:
- Scaling mode and aspect ratio are partly handled in core now.
Changes since v2:
- Split out the scaling mode / aspect ratio changes to a preparation
  patch.
- Use mode_changed for panel fitter, changes to this property
  are checked by fastset.
- Allowed_scaling_modes is removed, handled through core now.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20170501133804.8116-6-maarten.lankhorst@linux.intel.com

drivers/gpu/drm/i915/intel_drv.h

@@ -330,6 +330,15 @@ struct intel_connector {
 	struct work_struct modeset_retry_work;
 };
 
+struct intel_digital_connector_state {
+	struct drm_connector_state base;
+
+	enum hdmi_force_audio force_audio;
+	int broadcast_rgb;
+};
+
+#define to_intel_digital_connector_state(x) container_of(x, struct intel_digital_connector_state, base)
+
 struct dpll {
 	/* given values */
 	int n;
@@ -1912,6 +1921,20 @@ int intel_connector_atomic_get_property(struct drm_connector *connector,
 					const struct drm_connector_state *state,
 					struct drm_property *property,
 					uint64_t *val);
+
+int intel_digital_connector_atomic_get_property(struct drm_connector *connector,
+						const struct drm_connector_state *state,
+						struct drm_property *property,
+						uint64_t *val);
+int intel_digital_connector_atomic_set_property(struct drm_connector *connector,
+						struct drm_connector_state *state,
+						struct drm_property *property,
+						uint64_t val);
+int intel_digital_connector_atomic_check(struct drm_connector *conn,
+					 struct drm_connector_state *new_state);
+struct drm_connector_state *
+intel_digital_connector_duplicate_state(struct drm_connector *connector);
+
 struct drm_crtc_state *intel_crtc_duplicate_state(struct drm_crtc *crtc);
 void intel_crtc_destroy_state(struct drm_crtc *crtc,
 			       struct drm_crtc_state *state);