KVM: SVM: hyper-v: Enable Enlightened MSR-Bitmap support for real

KVM: SVM: hyper-v: Enable Enlightened MSR-Bitmap support for real

Commit c4327f15dfc7 ("KVM: SVM: hyper-v: Enlightened MSR-Bitmap support")
introduced enlightened MSR-Bitmap support for KVM-on-Hyper-V but it didn't
actually enable the support. Similar to enlightened NPT TLB flush and
direct TLB flush features, the guest (KVM) has to tell L0 (Hyper-V) that
it's using the feature by setting the appropriate feature fit in VMCB
control area (sw reserved fields).

Fixes: c4327f15dfc7 ("KVM: SVM: hyper-v: Enlightened MSR-Bitmap support")
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20211220152139.418372-3-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>