5-level EPT is present in Icelake Server CPUs and is supported by QEMU
('vmx-page-walk-5').

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20220221145316.576138-2-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>