fixed EP0 size to 64 since LS is not supported in device mode

- set turn-around and report actual speed in Enum Done
- add dcd_event_bus_reset() helper to report speed

src/device/dcd.h

@@ -60,11 +60,17 @@ typedef struct TU_ATTR_ALIGNED(4)
   uint8_t rhport;
   uint8_t event_id;
 
-  union {
-    // USBD_EVT_SETUP_RECEIVED
+  union
+  {
+    // BUS RESET
+    struct {
+      tusb_speed_t speed;
+    } bus_reset;
+
+    // SETUP_RECEIVED
     tusb_control_request_t setup_received;
 
-    // USBD_EVT_XFER_COMPLETE
+    // XFER_COMPLETE
     struct {
       uint8_t  ep_addr;
       uint8_t  result;
@@ -143,6 +149,9 @@ extern void dcd_event_handler(dcd_event_t const * event, bool in_isr);
 // helper to send bus signal event
 extern void dcd_event_bus_signal (uint8_t rhport, dcd_eventid_t eid, bool in_isr);
 
+// helper to send bus reset event
+extern void dcd_event_bus_reset (uint8_t rhport, tusb_speed_t speed, bool in_isr);
+
 // helper to send setup received
 extern void dcd_event_setup_received(uint8_t rhport, uint8_t const * setup, bool in_isr);