s390: implement diag318

x86:
* Report last CPU for debugging
* Emulate smaller MAXPHYADDR in the guest than in the host
* .noinstr and tracing fixes from Thomas
* nested SVM page table switching optimization and fixes

Generic:
* Unify shadow MMU cache data structures across architectures
Merge tag 'kvm-s390-next-5.9-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into kvm-next-5.6

KVM: s390: Enhancement for 5.9
- implement diagnose 318