KVM: x86: don't allow kernel irqchip with split irqchip

Split irqchip cannot be created after creating the kernel irqchip, but
we forgot to restrict the other way.  This is an API change.
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: NDavid Hildenbrand <david@redhat.com>
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/x86.c

@@ -3961,7 +3961,7 @@ long kvm_arch_vm_ioctl(struct file *filp,
 
 		mutex_lock(&kvm->lock);
 		r = -EEXIST;
-		if (kvm->arch.vpic)
+		if (irqchip_in_kernel(kvm))
 			goto create_irqchip_unlock;
 		r = -EINVAL;
 		if (kvm->created_vcpus)