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/char/mem.c b/drivers/char/mem.c
index 6c8b65d..a074fce 100644
--- a/drivers/char/mem.c
+++ b/drivers/char/mem.c
@@ -301,7 +301,7 @@
 }
 #endif
 
-static struct vm_operations_struct mmap_mem_ops = {
+static const struct vm_operations_struct mmap_mem_ops = {
 #ifdef CONFIG_HAVE_IOREMAP_PROT
 	.access = generic_access_phys
 #endif