i386/kvm: move Hyper-V CPUID filling to hyperv_handle_properties()

Let's consolidate Hyper-V features handling in hyperv_handle_properties().
The change is necessary to support 'hv-passthrough' mode as we'll be just
copying CPUIDs from KVM instead of filling them in.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20190517141924.19024-4-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>