USB: ti_usb_3410_5052: fix use-after-free in TIOCMIWAIT

USB: ti_usb_3410_5052: fix use-after-free in TIOCMIWAIT

commit fc98ab873aa3dbe783ce56a2ffdbbe7c7609521a upstream.

Use the port wait queue and make sure to check the serial disconnected
flag before accessing private port data after waking up.

This is is needed as the private port data (including the wait queue
itself) can be gone when waking up after a disconnect.

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>