chore(core): Disable wait_random() for prodtest and VCP.

[no changelog]

core/embed/trezorhal/stm32f4/random_delays.c

@@ -193,6 +193,7 @@ void rdi_handler(uint32_t uw_tick) {
  * against fault injection.
  */
 void wait_random(void) {
+#ifndef TREZOR_PRODTEST
   int wait = drbg_random8();
   volatile int i = 0;
   volatile int j = wait;
@@ -207,4 +208,5 @@ void wait_random(void) {
   if (i != wait || j != 0) {
     shutdown_privileged();
   }
+#endif
 }

core/embed/trezorhal/stm32f4/usb.c

@@ -490,7 +490,6 @@ static uint8_t usb_class_setup(USBD_HandleTypeDef *dev,
         wait_random();
         return usb_hid_class_setup(dev, &usb_ifaces[req->wIndex].hid, req);
       case USB_IFACE_TYPE_VCP:
-        wait_random();
         return usb_vcp_class_setup(dev, &usb_ifaces[req->wIndex].vcp, req);
       case USB_IFACE_TYPE_WEBUSB:
         wait_random();
@@ -516,7 +515,6 @@ static uint8_t usb_class_data_in(USBD_HandleTypeDef *dev, uint8_t ep_num) {
         usb_hid_class_data_in(dev, &usb_ifaces[i].hid, ep_num);
         break;
       case USB_IFACE_TYPE_VCP:
-        wait_random();
         usb_vcp_class_data_in(dev, &usb_ifaces[i].vcp, ep_num);
         break;
       case USB_IFACE_TYPE_WEBUSB:
@@ -541,7 +539,6 @@ static uint8_t usb_class_data_out(USBD_HandleTypeDef *dev, uint8_t ep_num) {
         usb_hid_class_data_out(dev, &usb_ifaces[i].hid, ep_num);
         break;
       case USB_IFACE_TYPE_VCP:
-        wait_random();
         usb_vcp_class_data_out(dev, &usb_ifaces[i].vcp, ep_num);
         break;
       case USB_IFACE_TYPE_WEBUSB:
@@ -559,7 +556,6 @@ static uint8_t usb_class_sof(USBD_HandleTypeDef *dev) {
   for (int i = 0; i < USBD_MAX_NUM_INTERFACES; i++) {
     switch (usb_ifaces[i].type) {
       case USB_IFACE_TYPE_VCP:
-        wait_random();
         usb_vcp_class_sof(dev, &usb_ifaces[i].vcp);
         break;
       default: