s390/stack: fix possible register corruption with stack switch helper
This is an automated ID intended to aid in discovery of potential security vulnerabilities. The actual impact and attack plausibility have not yet been proven. This ID is fixed in Linux Kernel version v5.13 by commit 67147e96a332b56c7206238162771d82467f86c0, it was introduced in version v4.20 by commit ff340d2472ec7618443913928af9fb85a7009270. For more details please see the references link.