drm/omap: drop unused DSS next pointer

Since all encoders and panels are using the bridge API now,
we next pointer is no longer useful and can be dropped.

Signed-off-by: Sebastian Reichel <[e-mail]>
Signed-off-by: Tomi Valkeinen <[e-mail]>
Reviewed-by: Laurent Pinchart <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/gpu/drm/omapdrm/dss/base.c

···
 			goto done;
 		}
 
-		if (dssdev->id && (dssdev->next || dssdev->bridge))
+		if (dssdev->id && dssdev->bridge)
 			goto done;
 	}
 

drivers/gpu/drm/omapdrm/dss/omapdss.h

···
 	struct module *owner;
 
 	struct dss_device *dss;
-	struct omap_dss_device *next;
 	struct drm_bridge *bridge;
 	struct drm_bridge *next_bridge;
 	struct drm_panel *panel;

drivers/gpu/drm/omapdrm/dss/output.c

···
 		return 0;
 	}
 
-	out->next = omapdss_find_device_by_node(remote_node);
 	out->bridge = of_drm_find_bridge(remote_node);
 	out->panel = of_drm_find_panel(remote_node);
 	if (IS_ERR(out->panel))
 		out->panel = NULL;
 
 	of_node_put(remote_node);
-
-	if (out->next && out->type != out->next->type) {
-		dev_err(out->dev, "output type and display type don't match\n");
-		ret = -EINVAL;
-		goto error;
-	}
 
 	if (out->panel) {
 		struct drm_bridge *bridge;
···
 		out->bridge = local_bridge;
 	}
 
-	if (!out->next && !out->bridge) {
+	if (!out->bridge) {
 		ret = -EPROBE_DEFER;
 		goto error;
 	}
···
 
 error:
 	omapdss_device_cleanup_output(out);
-	out->next = NULL;
 	return ret;
 }
 EXPORT_SYMBOL(omapdss_device_init_output);
···
 	if (out->bridge && out->panel)
 		drm_panel_bridge_remove(out->next_bridge ?
 					out->next_bridge : out->bridge);
-
-	if (out->next)
-		omapdss_device_put(out->next);
 }
 EXPORT_SYMBOL(omapdss_device_cleanup_output);
 

drivers/gpu/drm/omapdrm/omap_encoder.c

···
 {
 	struct omap_encoder *omap_encoder = to_omap_encoder(encoder);
 	struct omap_dss_device *output = omap_encoder->output;
-	struct omap_dss_device *dssdev;
 	struct drm_device *dev = encoder->dev;
 	struct drm_connector *connector;
 	struct drm_bridge *bridge;
···
 	 *
 	 * A better solution is to use DRM's bus-flags through the whole driver.
 	 */
-	for (dssdev = output; dssdev; dssdev = dssdev->next)
-		omap_encoder_update_videomode_flags(&vm, dssdev->bus_flags);
-
 	for (bridge = output->bridge; bridge;
 	     bridge = drm_bridge_get_next_bridge(bridge)) {
 		if (!bridge->timings)