kvm: fix compile on s390 part 2

We also need to fence the memunmap part.

Fixes: e45adf665a ("KVM: Introduce a new guest mapping API")
Fixes: d30b214d1d (kvm: fix compilation on s390)
Cc: Michal Kubecek <mkubecek@suse.cz>
Cc: KarimAllah Ahmed <karahmed@amazon.de>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>

virt/kvm/kvm_main.c

@@ -1795,8 +1795,10 @@ void kvm_vcpu_unmap(struct kvm_vcpu *vcpu, struct kvm_host_map *map,
 
 	if (map->page)
 		kunmap(map->page);
+#ifdef CONFIG_HAS_IOMEM
 	else
 		memunmap(map->hva);
+#endif
 
 	if (dirty) {
 		kvm_vcpu_mark_page_dirty(vcpu, map->gfn);