USB: pl2303: fix device initialisation at open

USB: pl2303: fix device initialisation at open

commit 2d8f4447b58bba5f8cb895c07690434c02307eaf upstream.

Do not use uninitialised termios data to determine when to configure the
device at open.

This also prevents stack data from leaking to userspace in the OOM error
path.

Signed-off-by: Johan Hovold <jhovold@gmail.com>
[bwh: Backported to 3.2: tty_struct::termios is a pointer, not a struct]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Cc: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>