iommu/vt-d: Constify intel_dma_ops

Most dma_map_ops structures are never modified. Constify these
structures such that these can be write-protected.
Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

drivers/iommu/intel-iommu.c

@@ -3954,7 +3954,7 @@ static int intel_mapping_error(struct device *dev, dma_addr_t dma_addr)
 	return !dma_addr;
 }
 
-struct dma_map_ops intel_dma_ops = {
+const struct dma_map_ops intel_dma_ops = {
 	.alloc = intel_alloc_coherent,
 	.free = intel_free_coherent,
 	.map_sg = intel_map_sg,