telephony: ijx: buffer overflow in ixj_write_cid()

[Not needed in 3.8 or newer as this driver is removed there. - gregkh]

We get this from user space and nothing has been done to ensure that
these strings are NUL terminated.

Reported-by: Chen Gang <gang.chen@asianux.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>