iommu/mediatek: Constify iommu_ops

iommu_ops are not supposed to change at runtime.
Functions 'iommu_device_set_ops' and 'bus_set_iommu' working with
const iommu_ops provided by <linux/iommu.h>. So mark the non-const
structs as const.

Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Signed-off-by: Yong Wu <yong.wu@mediatek.com>
(Change the title to iommu/mediatek: xx)
Signed-off-by: Joerg Roedel <jroedel@suse.de>

drivers/iommu/mtk_iommu.c

@@ -113,7 +113,7 @@ struct mtk_iommu_domain {
 	struct iommu_domain		domain;
 };
 
-static struct iommu_ops mtk_iommu_ops;
+static const struct iommu_ops mtk_iommu_ops;
 
 static LIST_HEAD(m4ulist);	/* List all the M4U HWs */
 
@@ -488,7 +488,7 @@ static int mtk_iommu_of_xlate(struct device *dev, struct of_phandle_args *args)
 	return iommu_fwspec_add_ids(dev, args->args, 1);
 }
 
-static struct iommu_ops mtk_iommu_ops = {
+static const struct iommu_ops mtk_iommu_ops = {
 	.domain_alloc	= mtk_iommu_domain_alloc,
 	.domain_free	= mtk_iommu_domain_free,
 	.attach_dev	= mtk_iommu_attach_device,

drivers/iommu/mtk_iommu_v1.c

@@ -362,7 +362,7 @@ static phys_addr_t mtk_iommu_iova_to_phys(struct iommu_domain *domain,
 	return pa;
 }
 
-static struct iommu_ops mtk_iommu_ops;
+static const struct iommu_ops mtk_iommu_ops;
 
 /*
  * MTK generation one iommu HW only support one iommu domain, and all the client
@@ -524,7 +524,7 @@ static int mtk_iommu_hw_init(const struct mtk_iommu_data *data)
 	return 0;
 }
 
-static struct iommu_ops mtk_iommu_ops = {
+static const struct iommu_ops mtk_iommu_ops = {
 	.domain_alloc	= mtk_iommu_domain_alloc,
 	.domain_free	= mtk_iommu_domain_free,
 	.attach_dev	= mtk_iommu_attach_device,