message: Remove unnecessary default implementation for driver
diff: @@ -58,12 +58,6 @@ impl NinedofDriver {
  }
  }
  -impl Default for NinedofDriver {
  - fn default() -> Self {
  - NinedofDriver
  - }
  -}
  -
  pub fn subscribe(cb: extern "C" fn(usize, usize, usize, usize), ud: usize) -> TockResult<()> {
  syscalls::subscribe_fn(DRIVER_NUM, 0, cb, ud)?;
  Ok(())
  