calipso: unlock rcu before returning -EAFNOSUPPORT

syzbot reported that a recent patch forgot to unlock rcu
in the error path.

Adopt the convention that netlbl_conn_setattr() is already using.

Fixes: 6e9f2df ("calipso: Don't call calipso functions for AF_INET sk.")
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Kuniyuki Iwashima <kuniyu@amazon.com>
Acked-by: Paul Moore <paul@paul-moore.com>
Link: https://patch.msgid.link/20250604133826.1667664-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: edumazet

net/netlabel/netlabel_kapi.c

@@ -1165,8 +1165,10 @@ int netlbl_conn_setattr(struct sock *sk,
 		break;
 #if IS_ENABLED(CONFIG_IPV6)
 	case AF_INET6:
-		if (sk->sk_family != AF_INET6)
-			return -EAFNOSUPPORT;
+		if (sk->sk_family != AF_INET6) {
+			ret_val = -EAFNOSUPPORT;
+			goto conn_setattr_return;
+		}
 
 		addr6 = (struct sockaddr_in6 *)addr;
 		entry = netlbl_domhsh_getentry_af6(secattr->domain,