[SPARC64]: Const'ify pci_iommu_ops.

Based upon a similar patch for x86_64 written by
Stephen Hemminger.
Signed-off-by: David S. Miller <davem@davemloft.net>

arch/sparc64/kernel/pci.c

@@ -282,10 +282,10 @@ int __init pcic_present(void)
 	return pci_controller_scan(pci_is_controller);
 }
 
-struct pci_iommu_ops *pci_iommu_ops;
+const struct pci_iommu_ops *pci_iommu_ops;
 EXPORT_SYMBOL(pci_iommu_ops);
 
-extern struct pci_iommu_ops pci_sun4u_iommu_ops,
+extern const struct pci_iommu_ops pci_sun4u_iommu_ops,
 	pci_sun4v_iommu_ops;
 
 /* Find each controller in the system, attach and initialize

arch/sparc64/kernel/pci_iommu.c

@@ -759,7 +759,7 @@ static void pci_4u_dma_sync_sg_for_cpu(struct pci_dev *pdev, struct scatterlist
 	spin_unlock_irqrestore(&iommu->lock, flags);
 }
 
-struct pci_iommu_ops pci_sun4u_iommu_ops = {
+const struct pci_iommu_ops pci_sun4u_iommu_ops = {
 	.alloc_consistent		= pci_4u_alloc_consistent,
 	.free_consistent		= pci_4u_free_consistent,
 	.map_single			= pci_4u_map_single,

arch/sparc64/kernel/pci_sun4v.c

@@ -583,7 +583,7 @@ static void pci_4v_dma_sync_sg_for_cpu(struct pci_dev *pdev, struct scatterlist
 	/* Nothing to do... */
 }
 
-struct pci_iommu_ops pci_sun4v_iommu_ops = {
+const struct pci_iommu_ops pci_sun4v_iommu_ops = {
 	.alloc_consistent		= pci_4v_alloc_consistent,
 	.free_consistent		= pci_4v_free_consistent,
 	.map_single			= pci_4v_map_single,

include/asm-sparc64/pci.h

@@ -54,7 +54,7 @@ struct pci_iommu_ops {
 	void (*dma_sync_sg_for_cpu)(struct pci_dev *, struct scatterlist *, int, int);
 };
 
-extern struct pci_iommu_ops *pci_iommu_ops;
+extern const struct pci_iommu_ops *pci_iommu_ops;
 
 /* Allocate and map kernel buffer using consistent mode DMA for a device.
  * hwdev should be valid struct pci_dev pointer for PCI devices.