drm/omap: Remove omap_dss_device dst field

The field is only used in a safety check during device
connection/disconnection, where the src field can be easily used
instead. Remove it and use src.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Tested-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

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

@@ -199,9 +199,8 @@ int omapdss_device_connect(struct dss_device *dss,
 	}
 
 	if (src) {
-		WARN_ON(src->dst);
+		WARN_ON(dst->src);
 		dst->src = src;
-		src->dst = dst;
 	}
 
 	return 0;
@@ -219,11 +218,10 @@ void omapdss_device_disconnect(struct omap_dss_device *src,
 	}
 
 	if (src) {
-		if (WARN_ON(dst != src->dst))
+		if (WARN_ON(dst->src != src))
 			return;
 
 		dst->src = NULL;
-		src->dst = NULL;
 	}
 
 	WARN_ON(dst->state != OMAP_DSS_DISPLAY_DISABLED);

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

@@ -406,7 +406,6 @@ struct omap_dss_device {
 
 	struct dss_device *dss;
 	struct omap_dss_device *src;
-	struct omap_dss_device *dst;
 	struct omap_dss_device *next;
 
 	struct list_head list;