Merge pull request #1179 from uestczyh222/master

[Components][Drivers][USB]fix memory leak

components/drivers/usb/usbdevice/class/hid.c

@@ -486,7 +486,10 @@ static rt_err_t _function_enable(ufunction_t func)
 //
 //    _vcom_reset_state(func);
 //
-    data->ep_out->buffer            = rt_malloc(HID_RX_BUFSIZE);
+    if(data->ep_out->buffer == RT_NULL)
+    {
+        data->ep_out->buffer        = rt_malloc(HID_RX_BUFSIZE);
+    }
     data->ep_out->request.buffer    = data->ep_out->buffer;
     data->ep_out->request.size      = EP_MAXPACKET(data->ep_out);
     data->ep_out->request.req_type  = UIO_REQUEST_READ_BEST;