Bluetooth: ISO: Check socket flag instead of hcon

This fixes the following Smatch static checker warning:

net/bluetooth/iso.c:1364 iso_sock_recvmsg()
error: we previously assumed 'pi->conn->hcon' could be null (line 1359)

net/bluetooth/iso.c
1347 static int iso_sock_recvmsg(struct socket *sock, struct msghdr *msg,
1348                             size_t len, int flags)
1349 {
1350         struct sock *sk = sock->sk;
1351         struct iso_pinfo *pi = iso_pi(sk);
1352
1353         BT_DBG("sk %p", sk);
1354
1355         if (test_and_clear_bit(BT_SK_DEFER_SETUP,
                                      &bt_sk(sk)->flags)) {
1356                 lock_sock(sk);
1357                 switch (sk->sk_state) {
1358                 case BT_CONNECT2:
1359                         if (pi->conn->hcon &&
                                     ^^^^^^^^^^^^^^ If ->hcon is NULL

1360                             test_bit(HCI_CONN_PA_SYNC,
                                         &pi->conn->hcon->flags)) {
1361                                 iso_conn_big_sync(sk);
1362                                 sk->sk_state = BT_LISTEN;
1363                         } else {
--> 1364                         iso_conn_defer_accept(pi->conn->hcon);
                                                       ^^^^^^^^^^^^^^
                                                       then we're toast

1365                                 sk->sk_state = BT_CONFIG;
1366                         }
1367                         release_sock(sk);
1368                         return 0;
1369                 case BT_CONNECTED:
1370                         if (test_bit(BT_SK_PA_SYNC,

Fixes: fbdc4bc4

 ("Bluetooth: ISO: Use defer setup to separate PA sync and BIG sync")
Signed-off-by: Iulia Tanasescu <iulia.tanasescu@nxp.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>