Bluetooth: Add return check for L2CAP security level set

Add return check for security level set for socket interface since
stack will check the return value.
Signed-off-by: Fugang Duan <fugang.duan@nxp.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

net/bluetooth/l2cap_sock.c

@@ -791,10 +791,13 @@ static int l2cap_sock_setsockopt(struct socket *sock, int level, int optname,
 
 		conn = chan->conn;
 
-		/*change security for LE channels */
+		/* change security for LE channels */
 		if (chan->scid == L2CAP_CID_ATT) {
-			if (smp_conn_security(conn->hcon, sec.level))
+			if (smp_conn_security(conn->hcon, sec.level)) {
+				err = -EINVAL;
 				break;
+			}
+
 			set_bit(FLAG_PENDING_SECURITY, &chan->flags);
 			sk->sk_state = BT_CONFIG;
 			chan->state = BT_CONFIG;