KVM: x86: properly restore LVT0

commit db138562 upstream.

Legacy NMI watchdog didn't work after migration/resume, because
vapics_in_nmi_mode was left at 0.

Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>