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

Check for the ->map and not the ->unmap pointer.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 1698360..ac4adb3 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -995,7 +995,7 @@
 	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;