iommu: Do not call domain_alloc() in iommu_sva_domain_alloc()

No driver implements SVA under domain_alloc() anymore, this is dead
code.

Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Link: https://lore.kernel.org/r/4-v4-ff5fb6b03bd1+288-iommu_virtio_domains_jgg@nvidia.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>

Author: jgunthorpe

drivers/iommu/iommu-sva.c

@@ -296,15 +296,12 @@ static struct iommu_domain *iommu_sva_domain_alloc(struct device *dev,
 	const struct iommu_ops *ops = dev_iommu_ops(dev);
 	struct iommu_domain *domain;
 
-	if (ops->domain_alloc_sva) {
-		domain = ops->domain_alloc_sva(dev, mm);
-		if (IS_ERR(domain))
-			return domain;
-	} else {
-		domain = ops->domain_alloc(IOMMU_DOMAIN_SVA);
-		if (!domain)
-			return ERR_PTR(-ENOMEM);
-	}
+	if (!ops->domain_alloc_sva)
+		return ERR_PTR(-EOPNOTSUPP);
+
+	domain = ops->domain_alloc_sva(dev, mm);
+	if (IS_ERR(domain))
+		return domain;
 
 	domain->type = IOMMU_DOMAIN_SVA;
 	domain->cookie_type = IOMMU_COOKIE_SVA;