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>
[lizf: Backported to 3.4:
 - adjust context
 - s/kvm_apic_get_reg/apic_get_reg/]
Signed-off-by: Zefan Li <lizefan@huawei.com>