Revert "Fix EP0 receiving more packets."

This reverts commit e58e134b42.

--

The fix was no-op, because following code does not use LEN at all.
For other machines, it uses LEN for hardware USB core.

mcu/usb-st-common.c

@@ -864,8 +864,6 @@ usb_lld_ctrl_recv (struct usb_dev *dev, void *p, size_t len)
   struct ctrl_data *data_p = &dev->ctrl_data;
   data_p->addr = p;
   data_p->len = len;
-  if (len > USB_MAX_PACKET_SIZE)
-    len = USB_MAX_PACKET_SIZE;
   dev->state = OUT_DATA;
   ep_set_rx_status (ENDP0, EP_RX_VALID);
   return USB_EVENT_OK;