USB: opticon: fix memory leak in error path

commit acbf0e5263de563e25f7c104868e4490b9e72b13 upstream.

Fix memory leak in write error path.

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>