KVM: PPC: Enable IOMMU_API for KVM_BOOK3S_64 permanently

It does not make much sense to have KVM in book3s-64 and
not to have IOMMU bits for PCI pass through support as it costs little
and allows VFIO to function on book3s KVM.

Having IOMMU_API always enabled makes it unnecessary to have a lot of
"#ifdef IOMMU_API" in arch/powerpc/kvm/book3s_64_vio*. With those
ifdef's we could have only user space emulated devices accelerated
(but not VFIO) which do not seem to be very useful.
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>

arch/powerpc/kvm/Kconfig

@@ -67,6 +67,7 @@ config KVM_BOOK3S_64
 	select KVM_BOOK3S_64_HANDLER
 	select KVM
 	select KVM_BOOK3S_PR_POSSIBLE if !KVM_BOOK3S_HV_POSSIBLE
+	select SPAPR_TCE_IOMMU if IOMMU_SUPPORT
 	---help---
 	  Support running unmodified book3s_64 and book3s_32 guest kernels
 	  in virtual machines on book3s_64 host processors.