dm crypt: Constify static crypt_iv_operations

The only usage of these structs is to assign their address to the
iv_gen_ops field in the crypt config struct, which is a pointer to
const. Make them const like the rest of the static crypt_iv_operations
structs. This allows the compiler to put them in read-only memory.
Signed-off-by: Rikard Falkeborn <rikard.falkeborn@gmail.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

drivers/md/dm-crypt.c

@@ -1090,16 +1090,16 @@ static const struct crypt_iv_operations crypt_iv_tcw_ops = {
 	.post	   = crypt_iv_tcw_post
 };
 
-static struct crypt_iv_operations crypt_iv_random_ops = {
+static const struct crypt_iv_operations crypt_iv_random_ops = {
 	.generator = crypt_iv_random_gen
 };
 
-static struct crypt_iv_operations crypt_iv_eboiv_ops = {
+static const struct crypt_iv_operations crypt_iv_eboiv_ops = {
 	.ctr	   = crypt_iv_eboiv_ctr,
 	.generator = crypt_iv_eboiv_gen
 };
 
-static struct crypt_iv_operations crypt_iv_elephant_ops = {
+static const struct crypt_iv_operations crypt_iv_elephant_ops = {
 	.ctr	   = crypt_iv_elephant_ctr,
 	.dtr	   = crypt_iv_elephant_dtr,
 	.init	   = crypt_iv_elephant_init,