SafeSetID: fix UID printed instead of GID

pr_warn message clearly says that GID should be printed,
but we have UID there. Let's fix that.

Found accidentally during the work on isolated user namespaces.
Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
[PM: fix spelling errors in description, subject tweak]
Signed-off-by: Paul Moore <paul@paul-moore.com>

security/safesetid/lsm.c

@@ -131,7 +131,7 @@ static int safesetid_security_capable(const struct cred *cred,
 		 * set*gid() (e.g. setting up userns gid mappings).
 		 */
 		pr_warn("Operation requires CAP_SETGID, which is not available to GID %u for operations besides approved set*gid transitions\n",
-			__kuid_val(cred->uid));
+			__kgid_val(cred->gid));
 		return -EPERM;
 	default:
 		/* Error, the only capabilities were checking for is CAP_SETUID/GID */