ANDROID: KVM: arm64: iommu: Allow to boot without IOMMU driver

For bringup purpose, allow pKVM to initialize without IOMMU driver.

Bug: 384432312
Change-Id: Id7d972f1c0e191afc46471a4f073aed606a42617
Signed-off-by: Mostafa Saleh <smostafa@google.com>

arch/arm64/kvm/hyp/nvhe/iommu/iommu.c

@@ -153,7 +153,7 @@ int kvm_iommu_init(void)
 	    !kvm_iommu_ops->init ||
 	    !kvm_iommu_ops->alloc_domain ||
 	    !kvm_iommu_ops->free_domain)
-		return -ENODEV;
+		return 0;
 
 	ret = hyp_pool_init_empty(&iommu_host_pool, 64);
 	if (ret)

arch/arm64/kvm/iommu.c

@@ -37,7 +37,7 @@ int kvm_iommu_init_driver(void)
 {
 	if (WARN_ON(!smp_load_acquire(&iommu_driver))) {
 		kvm_err("pKVM enabled without an IOMMU driver, do not run confidential workloads in virtual machines\n");
-		return -ENODEV;
+		return 0;
 	}
 
 	kvm_hyp_iommu_domains = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,