KVM: x86: fix the error of ioctl KVM_IRQ_LINE if no irq chip

If no irq chip in kernel, ioctl KVM_IRQ_LINE will return -EFAULT.
But I see in other place such as KVM_[GET|SET]IRQCHIP, -ENXIO is
return. So this patch used -ENXIO instead of -EFAULT.
Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

arch/x86/kvm/x86.c

@@ -2836,11 +2836,13 @@ long kvm_arch_vm_ioctl(struct file *filp,
 		r = -EFAULT;
 		if (copy_from_user(&irq_event, argp, sizeof irq_event))
 			goto out;
+		r = -ENXIO;
 		if (irqchip_in_kernel(kvm)) {
 			__s32 status;
 			status = kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID,
 					irq_event.irq, irq_event.level);
 			if (ioctl == KVM_IRQ_LINE_STATUS) {
+				r = -EFAULT;
 				irq_event.status = status;
 				if (copy_to_user(argp, &irq_event,
 							sizeof irq_event))