staging/ozwpan: info leak in oz_cdev_ioctl()

If we're not maxed out then oz_get_pd_list() leaves part of the "list"
struct uninitialized.  We should clear this so that no stack information
is leaked to userspace.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>