KVM: x86: hyper-v: Inverse the default in hv_check_msr_access()

Access to all MSRs is now properly checked. To avoid 'forgetting' to
properly check access to new MSRs in the future change the default
to 'false' meaning 'no access'.

No functional change intended.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20210521095204.2161214-19-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>