KVM: x86: Introducing kvm_x86_ops VM init/destroy hooks

KVM: x86: Introducing kvm_x86_ops VM init/destroy hooks

Adding function pointers in struct kvm_x86_ops for processor-specific
layer to provide hooks for when KVM initialize and destroy VM.

Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Orabug: 28220674
CVE: CVE-2018-3646

(cherry picked from commit 03543133cea646406307870823343912c1ef0a3a)

Signed-off-by: Mihai Carabas <mihai.carabas@oracle.com>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Conflicts:
	arch/x86/kvm/x86.c
Contextual: different content
The commit was necessary for 47009da5 "x86/KVM: Warn user if KVM
is loaded SMT and L1TF CPU bug being present"