ima: bugfix for digest lists importing

hulk inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I4XHBM


CVE: NA

-------------

The check for control character shouldn't be added when import a
binary digest list.

Signed-off-by: shenxiangwei <shenxiangwei1@huawei.com>
Reviewed-by: Lu Huaxin <luhuaxin1@huawei.com>
Reviewed-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>