Two fixes for recently introduced regressions
- a memory leak on busy SIGP
- pontentially lost SIGP stop in rare situations (shutdown loops)
The first issue is not part of a released kernel. The 2nd issue is
present in all KVM versions, but did not trigger before commit
1484378517e6aa73e49cf5b0c63 (KVM: s390: allow only one SIGP STOP
(AND STORE STATUS) at a time) with Linux as a guest.
So no need for cc stable