usb: gadget: configfs: Fix missing spin_lock_init()

The driver allocates the spinlock but not initialize it.
Use spin_lock_init() on it to initialize it correctly.

This is detected by Coccinelle semantic patch.

Fixes: 1a1c851bbd ("usb: gadget: configfs: fix concurrent issue between composite APIs")
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Cc: stable <stable@vger.kernel.org>
Reviewed-by: Peter Chen <peter.chen@nxp.com>
Link: https://lore.kernel.org/r/20191030034046.188808-1-weiyongjun1@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/gadget/configfs.c

@@ -1544,6 +1544,7 @@ static struct config_group *gadgets_make(
 	gi->composite.resume = NULL;
 	gi->composite.max_speed = USB_SPEED_SUPER;
 
+	spin_lock_init(&gi->spinlock);
 	mutex_init(&gi->lock);
 	INIT_LIST_HEAD(&gi->string_list);
 	INIT_LIST_HEAD(&gi->available_func);