const: mark struct vm_struct_operations

* mark struct vm_area_struct::vm_ops as const
* mark vm_ops in AGP code

But leave TTM code alone, something is fishy there with global vm_ops
being used.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/ieee1394/dma.c b/drivers/ieee1394/dma.c
index 1aba8c1..8e7e334 100644
--- a/drivers/ieee1394/dma.c
+++ b/drivers/ieee1394/dma.c
@@ -247,7 +247,7 @@
 	return 0;
 }
 
-static struct vm_operations_struct dma_region_vm_ops = {
+static const struct vm_operations_struct dma_region_vm_ops = {
 	.fault = dma_region_pagefault,
 };