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>

drivers/usb/gadget/nokia.c

@@ -242,12 +242,13 @@ static __refdata struct usb_composite_driver nokia_driver = {
 	.dev		= &device_desc,
 	.strings	= dev_strings,
 	.max_speed	= USB_SPEED_HIGH,
+	.bind		= nokia_bind,
 	.unbind		= __exit_p(nokia_unbind),
 };
 
 static int __init nokia_init(void)
 {
-	return usb_composite_probe(&nokia_driver, nokia_bind);
+	return usb_composite_probe(&nokia_driver);
 }
 module_init(nokia_init);