s390/pkey: zeroize key blobs

stable inclusion
from stable-v5.10.183
commit 046721280664d1b6c39bef2e3012553a975ac979
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I8IRR2

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=046721280664d1b6c39bef2e3012553a975ac979



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[ Upstream commit 844cf829 ]

Key blobs for the IOCTLs PKEY_KBLOB2PROTK[23] may contain clear key
material. Zeroize the copies of these keys in kernel memory after
creating the protected key.

Reviewed-by: Harald Freudenberger <freude@linux.ibm.com>
Signed-off-by: Holger Dengler <dengler@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: sanglipeng <sanglipeng1@jd.com>