USB: serial: fix tty cleanup-op kernel-doc

The tty cleanup operation is called with a struct tty as its sole
parameter.

Signed-off-by: Johan Hovold <[e-mail]>

drivers/usb/serial/usb-serial.c

···
 
 /**
  * serial_cleanup - free resources post close/hangup
- * @port: port to free up
+ * @tty: tty to clean up
  *
  * Do the resource freeing and refcount dropping for the port.
  * Avoid freeing the console.