drm/bridge: lt8912b: Add missing drm_bridge_attach call

The driver does not call drm_bridge_attach(), which causes the next
bridge to not be added to the bridge chain. This causes the pipeline
init to fail when DRM_BRIDGE_ATTACH_NO_CONNECTOR is used.

Add the call to drm_bridge_attach().

Fixes: 30e2ae94 ("drm/bridge: Introduce LT8912B DSI to HDMI bridge")
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Reviewed-by: Robert Foss <rfoss@kernel.org>
Signed-off-by: Robert Foss <rfoss@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230804-lt8912b-v1-4-c542692c6a2f@ideasonboard.com

drivers/gpu/drm/bridge/lontium-lt8912b.c

@@ -558,6 +558,13 @@ static int lt8912_bridge_attach(struct drm_bridge *bridge,
 	struct lt8912 *lt = bridge_to_lt8912(bridge);
 	int ret;
 
+	ret = drm_bridge_attach(bridge->encoder, lt->hdmi_port, bridge,
+				DRM_BRIDGE_ATTACH_NO_CONNECTOR);
+	if (ret < 0) {
+		dev_err(lt->dev, "Failed to attach next bridge (%d)\n", ret);
+		return ret;
+	}
+
 	if (!(flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR)) {
 		ret = lt8912_bridge_connector_init(bridge);
 		if (ret) {