usb: gadget: printer: revert usb_add_function() effect in error recovery

Whenever the "goto fail" branch is taken, the effect of usb_add_function()
should be reverted.
Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/gadget/legacy/printer.c

@@ -1285,6 +1285,7 @@ static int __init printer_bind_config(struct usb_configuration *c)
 
 fail:
 	printer_cfg_unbind(c);
+	usb_remove_function(c, &dev->function);
 	return status;
 }