usb: gadget: move bind() callback back to struct usb_composite_driver

This partly reverts 07a18bd7 ("usb gadget: don't save bind callback in
struct usb_composite_driver") and fixes new drivers. The section missmatch
problems was solved by whitelisting structs in question via __ref.

Cc: devel@driverdev.osuosl.org
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Felipe Balbi <balbi@ti.com>
diff --git a/include/linux/usb/composite.h b/include/linux/usb/composite.h
index 3153f73..19a5adf 100644
--- a/include/linux/usb/composite.h
+++ b/include/linux/usb/composite.h
@@ -305,8 +305,7 @@
 	void			(*resume)(struct usb_composite_dev *);
 };
 
-extern int usb_composite_probe(struct usb_composite_driver *driver,
-			       int (*bind)(struct usb_composite_dev *cdev));
+extern int usb_composite_probe(struct usb_composite_driver *driver);
 extern void usb_composite_unregister(struct usb_composite_driver *driver);
 extern void usb_composite_setup_continue(struct usb_composite_dev *cdev);