USB: usb.h: change private: kernel-doc for new format requirement

Use "/* private:" to mark struct members as private so that
scripts/kernel-doc will handle them correctly.
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Acked-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

include/linux/usb.h

@@ -1421,8 +1421,8 @@ struct usb_sg_request {
 	int			status;
 	size_t			bytes;
 
-	/*
-	 * members below are private: to usbcore,
+	/* private:
+	 * members below are private to usbcore,
 	 * and are not provided for driver access!
 	 */
 	spinlock_t		lock;