Currently an enabled break state is not disabled on final close nor on
re-open and has to be disabled manually.
Fix this by disabling break on port shutdown.
Reported-by: Jari Ruusu <jariruusu@users.sourceforge.net> Tested-by: Jari Ruusu <jariruusu@users.sourceforge.net> Signed-off-by: Johan Hovold <johan@kernel.org>