KVM: Introduce kvm_vcpu_destroy()

Add kvm_vcpu_destroy() and wire up all architectures to call the common
function instead of their arch specific implementation.  The common
destruction function will be used by future patches to move allocation
and initialization of vCPUs to common KVM code, i.e. to free resources
that are allocated by arch agnostic code.

No functional change intended.

Acked-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 335762a..42b9149 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -9680,7 +9680,7 @@ static void kvm_free_vcpus(struct kvm *kvm)
 		kvm_unload_vcpu_mmu(vcpu);
 	}
 	kvm_for_each_vcpu(i, vcpu, kvm)
-		kvm_arch_vcpu_destroy(vcpu);
+		kvm_vcpu_destroy(vcpu);
 
 	mutex_lock(&kvm->lock);
 	for (i = 0; i < atomic_read(&kvm->online_vcpus); i++)