kvm-4.15-2

* GICv4 Support for KVM/ARM

All ARM patches were in next-20171113.  I have postponed most x86 fixes
to 4.15-rc2 and UMIP to 4.16, but there are fixes that would be good to
have already in 4.15-rc1:

* re-introduce support for CPUs without virtual NMI (cc stable)
  and allow testing of KVM without virtual NMI on available CPUs

* fix long-standing performance issues with assigned devices on AMD
  (cc stable)