iommu/core: Check for the right function pointer in iommu_map()

Check for the ->map and not the ->unmap pointer.
Signed-off-by: NJoerg Roedel <jroedel@suse.de>

drivers/iommu/iommu.c

@@ -995,7 +995,7 @@ int iommu_map(struct iommu_domain *domain, unsigned long iova,
 	size_t orig_size = size;
 	int ret = 0;
 
-	if (unlikely(domain->ops->unmap == NULL ||
+	if (unlikely(domain->ops->map == NULL ||
 		     domain->ops->pgsize_bitmap == 0UL))
 		return -ENODEV;