usb: remove msos-descriptor feature.

examples/stm32l4/src/bin/usb_serial.rs

@@ -72,6 +72,7 @@ async fn main(_spawner: Spawner) {
         &mut device_descriptor,
         &mut config_descriptor,
         &mut bos_descriptor,
+        &mut [], // no msos descriptors
         &mut control_buf,
     );