usb: propagate submit_xfer result

The result is used in the example but was not actually propagated.
With this result, the report double buffering will work correctly.

Signed-off-by: Hyx <[email protected]>

Author: hyx0329

micropython/usb/usb-device-hid/usb/device/hid.py

@@ -122,7 +122,7 @@ def send_report(self, report_data, timeout_ms=100):
             machine.idle()
         if not self.is_open():
             return False
-        self.submit_xfer(self._int_ep, report_data)
+        return self.submit_xfer(self._int_ep, report_data)
 
     def desc_cfg(self, desc, itf_num, ep_num, strs):
         # Add the standard interface descriptor

micropython/usb/usb-device/usb/device/core.py

@@ -600,7 +600,7 @@ def submit_xfer(self, ep_addr, data, done_cb=None):
         # function has returned to the caller.
         if not self._open:
             raise RuntimeError("Not open")
-        _dev._submit_xfer(ep_addr, data, done_cb)
+        return _dev._submit_xfer(ep_addr, data, done_cb)
 
     def stall(self, ep_addr, *args):
         # Set or get the endpoint STALL state.