add const for printer device_id

class/printer/usbd_printer.c

@@ -7,7 +7,7 @@
 #include "usbd_printer.h"
 
 struct printer_cfg_priv {
-    uint8_t *device_id;
+    const uint8_t *device_id;
     uint8_t device_id_len;
     uint8_t port_status;
 } usbd_printer_cfg;
@@ -58,4 +58,4 @@ struct usbd_interface *usbd_printer_init_intf(struct usbd_interface *intf, const
     usbd_printer_cfg.device_id = device_id;
     usbd_printer_cfg.device_id_len = device_id_len;
     return intf;
-}
+}