lsm: replace the name field with a pointer to the lsm_id struct

Reduce the duplication between the lsm_id struct and the DEFINE_LSM()
definition by linking the lsm_id struct directly into the individual
LSM's DEFINE_LSM() instance.

Linking the lsm_id into the LSM definition also allows us to simplify
the security_add_hooks() function by removing the code which populates
the lsm_idlist[] array and moving it into the normal LSM startup code
where the LSM list is parsed and the individual LSMs are enabled,
making for a cleaner implementation with less overhead at boot.

Reviewed-by: Kees Cook <kees@kernel.org>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>

security/tomoyo/tomoyo.c

@@ -612,7 +612,7 @@ static int __init tomoyo_init(void)
 }
 
 DEFINE_LSM(tomoyo) = {
-	.name = "tomoyo",
+	.id = &tomoyo_lsmid,
 	.enabled = &tomoyo_enabled,
 	.flags = LSM_FLAG_LEGACY_MAJOR,
 	.blobs = &tomoyo_blob_sizes,