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/arch/x86/pci/i386.c b/arch/x86/pci/i386.c
index 52e62e5..b22d13b 100644
--- a/arch/x86/pci/i386.c
+++ b/arch/x86/pci/i386.c
@@ -266,7 +266,7 @@
 	pci_write_config_byte(dev, PCI_LATENCY_TIMER, lat);
 }
 
-static struct vm_operations_struct pci_mmap_ops = {
+static const struct vm_operations_struct pci_mmap_ops = {
 	.access = generic_access_phys,
 };