KVM: x86: really disarm lapic timer when clearing TMICT

preemption timer only looks at tscdeadline and could inject already
disarmed timer.
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Reviewed-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/lapic.c

@@ -1489,8 +1489,10 @@ static bool set_target_expiration(struct kvm_lapic *apic)
 	apic->lapic_timer.period = (u64)kvm_lapic_get_reg(apic, APIC_TMICT)
 		* APIC_BUS_CYCLE_NS * apic->divide_count;
 
-	if (!apic->lapic_timer.period)
+	if (!apic->lapic_timer.period) {
+		apic->lapic_timer.tscdeadline = 0;
 		return false;
+	}
 
 	limit_periodic_timer_frequency(apic);