greybus: core: fix greybus device matching

The bus code should only match bundle devices for now, and must not
assume all greybus devices are bundles.
Signed-off-by: Johan Hovold <johan@hovoldconsulting.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

drivers/staging/greybus/core.c

@@ -65,9 +65,14 @@ greybus_match_id(struct gb_bundle *bundle, const struct greybus_bundle_id *id)
 static int greybus_module_match(struct device *dev, struct device_driver *drv)
 {
 	struct greybus_driver *driver = to_greybus_driver(drv);
-	struct gb_bundle *bundle = to_gb_bundle(dev);
+	struct gb_bundle *bundle;
 	const struct greybus_bundle_id *id;
 
+	if (!is_gb_bundle(dev))
+		return 0;
+
+	bundle = to_gb_bundle(dev);
+
 	id = greybus_match_id(bundle, driver->id_table);
 	if (id)
 		return 1;