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>

fs/xfs/linux-2.6/xfs_file.c

@@ -42,7 +42,7 @@
 
 #include <linux/dcache.h>
 
-static struct vm_operations_struct xfs_file_vm_ops;
+static const struct vm_operations_struct xfs_file_vm_ops;
 
 STATIC ssize_t
 xfs_file_aio_read(
@@ -280,7 +280,7 @@ const struct file_operations xfs_dir_file_operations = {
 	.fsync		= xfs_file_fsync,
 };
 
-static struct vm_operations_struct xfs_file_vm_ops = {
+static const struct vm_operations_struct xfs_file_vm_ops = {
 	.fault		= filemap_fault,
 	.page_mkwrite	= xfs_vm_page_mkwrite,
 };