This 'memmap_ktype' is not modified. It is only used in
firmware_map_add_entry().

Constifying this structure and moving it to a read-only section,
and this can increase over all security.

```
[Before]
   text    data     bss     dec     hex filename
   4345     596      12    4953    1359 drivers/firmware/memmap.o

[After]
   text    data     bss     dec     hex filename
   4393     548      12    4953    1359 drivers/firmware/memmap.o
```

Signed-off-by: Kunwu Chan <chentao@kylinos.cn>
---
 drivers/firmware/memmap.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/firmware/memmap.c b/drivers/firmware/memmap.c
index 8e59be3782cb..55b9cfad8a04 100644
--- a/drivers/firmware/memmap.c
+++ b/drivers/firmware/memmap.c
@@ -116,7 +116,7 @@ static void __meminit release_firmware_map_entry(struct kobject *kobj)
 	kfree(entry);
 }
 
-static struct kobj_type __refdata memmap_ktype = {
+static const struct kobj_type memmap_ktype = {
 	.release	= release_firmware_map_entry,
 	.sysfs_ops	= &memmap_attr_ops,
 	.default_groups	= def_groups,
-- 
2.41.0