ima: Evaluate error in init_ima()

mainline inclusion
from mainline-v5.8-rc1
commit e144d6b2
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I692HU


CVE: NA

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

Evaluate error in init_ima() before register_blocking_lsm_notifier() and
return if not zero.

Cc: stable@vger.kernel.org # 5.3.x
Fixes: b1694245 ("ima: use the lsm policy update notifier")
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Reviewed-by: James Morris <jamorris@linux.microsoft.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: GUO Zihua <guozihua@huawei.com>
Reviewed-by: Xiu Jianfeng <xiujianfeng@huawei.com>
Signed-off-by: Yongqiang Liu <liuyongqiang13@huawei.com>