KVM: x86: Avoid using plain integer as NULL pointer warning

This patch fix the following sparse warning:

for file arch/x86/kvm/x86.c:
warning: Using plain integer as NULL pointer

Signed-off-by: Xiubo Li <lixiubo@cmss.chinamobile.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index d1a1fea..1309263 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -5919,7 +5919,7 @@
 	lapic_irq.dest_id = apicid;
 
 	lapic_irq.delivery_mode = APIC_DM_REMRD;
-	kvm_irq_delivery_to_apic(kvm, 0, &lapic_irq, NULL);
+	kvm_irq_delivery_to_apic(kvm, NULL, &lapic_irq, NULL);
 }
 
 int kvm_emulate_hypercall(struct kvm_vcpu *vcpu)