devices: remove whitespace

Rust 1.38 fmt complains about an extra whitespace.

Signed-off-by: Andreea Florescu <[email protected]>

Author: andreeaflorescu

devices/src/virtio/vsock/device.rs

@@ -300,5 +300,4 @@ mod tests {
             )
             .unwrap();
     }
-
 }