scsi: target: tcmu: Constify some structures

'struct nla_policy' and 'struct match_table_t' are not modified in this
driver.

Constifying these structures moves some data to a read-only section, so
increase overall security, especially when the structure holds some
function pointers, which is the case of struct nla_policy.

On a x86_64, with allmodconfig:
Before:
======
   text	   data	    bss	    dec	    hex	filename
  93188	   6933	    338	 100459	  1886b	drivers/target/target_core_user.o

After:
=====
   text	   data	    bss	    dec	    hex	filename
  93508	   6581	    338	 100427	  1884b	drivers/target/target_core_user.o

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/f83cd8469cc17391178e1181e8c26c4c1fb6028f.1731330634.git.christophe.jaillet@wanadoo.fr
Reviewed-by: Bodo Stroesser <bostroesser@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

Author: tititiou36

drivers/target/target_core_user.c

@@ -361,7 +361,7 @@ static const struct genl_multicast_group tcmu_mcgrps[] = {
 	[TCMU_MCGRP_CONFIG] = { .name = "config", },
 };
 
-static struct nla_policy tcmu_attr_policy[TCMU_ATTR_MAX+1] = {
+static const struct nla_policy tcmu_attr_policy[TCMU_ATTR_MAX + 1] = {
 	[TCMU_ATTR_DEVICE]	= { .type = NLA_STRING },
 	[TCMU_ATTR_MINOR]	= { .type = NLA_U32 },
 	[TCMU_ATTR_CMD_STATUS]	= { .type = NLA_S32 },
@@ -2430,7 +2430,7 @@ enum {
 	Opt_cmd_ring_size_mb, Opt_err,
 };
 
-static match_table_t tokens = {
+static const match_table_t tokens = {
 	{Opt_dev_config, "dev_config=%s"},
 	{Opt_dev_size, "dev_size=%s"},
 	{Opt_hw_block_size, "hw_block_size=%d"},