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/media/video/videobuf-vmalloc.c b/drivers/media/video/videobuf-vmalloc.c
index 30ae30f..35f3900 100644
--- a/drivers/media/video/videobuf-vmalloc.c
+++ b/drivers/media/video/videobuf-vmalloc.c
@@ -116,7 +116,7 @@
 	return;
 }
 
-static struct vm_operations_struct videobuf_vm_ops =
+static const struct vm_operations_struct videobuf_vm_ops =
 {
 	.open     = videobuf_vm_open,
 	.close    = videobuf_vm_close,