ser_gigaset: fix memory leak

[Paul Bolle]

Hi Dmitry,

I've cobbled together a two part series to fix the leak syzkaller uncovered in
ser_gigaset. I'd really appreciate it if you'd unleash syzkaller on this small
series one more time. Just to be sure that this also fixes the leak on your box
and that it doesn't introduce neww horrors.

Thanks,


Paul Bolle