iommu: Constify struct iommu_ops

This structure is read-only data and should never be modified.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
diff --git a/include/linux/device.h b/include/linux/device.h
index af424ac..75f5bcb 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -124,7 +124,7 @@
 
 	const struct dev_pm_ops *pm;
 
-	struct iommu_ops *iommu_ops;
+	const struct iommu_ops *iommu_ops;
 
 	struct subsys_private *p;
 	struct lock_class_key lock_key;