KVM: PIT: unregister kvm irq notifier if fail to create pit

If fail to create pit, we should unregister kvm irq notifier
which register in kvm_create_pit().
Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Acked-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

arch/x86/kvm/i8254.c

@@ -663,7 +663,8 @@ fail_unregister:
 	kvm_io_bus_unregister_dev(kvm, KVM_PIO_BUS, &pit->dev);
 
 fail:
-	if (pit->irq_source_id >= 0)
+	kvm_unregister_irq_mask_notifier(kvm, 0, &pit->mask_notifier);
+	kvm_unregister_irq_ack_notifier(kvm, &pit_state->irq_ack_notifier);
 	kvm_free_irq_source_id(kvm, pit->irq_source_id);
 
 	kfree(pit);