nimble/ll: Fix creating connections with all-zero IRK

If peer was added using LE Add Device To Resolving List Command and
provided peer IRK is all zeros we should stil accept connection with
it's public (or static random) random even if in network privacy mode.

This was affecting TP/CON/INI/BV-08-C qualification test case.

Author: sjanc

nimble/controller/src/ble_ll_conn.c

@@ -2770,10 +2770,17 @@ ble_ll_conn_is_peer_adv(uint8_t addr_type, uint8_t *adva, int index)
     case BLE_HCI_CONN_PEER_ADDR_RANDOM:
         if (addr_type == connsm->peer_addr_type) {
 #if (MYNEWT_VAL(BLE_LL_CFG_FEAT_LL_PRIVACY) == 1)
-                /* Peer uses its identity address. Let's verify privacy mode*/
+                /* Peer uses its identity address. Let's verify privacy mode.
+                 *
+                 * Note: Core Spec 5.0 Vol 6, Part B
+                 * If the Host has added the peer device to the resolving list
+                 * with an all-zero peer IRK, the Controller shall only accept
+                 * the peer's identity address.
+                 */
             if (ble_ll_resolv_enabled()) {
                 rl = ble_ll_resolv_list_find(adva, addr_type);
-                if (rl && (rl->rl_priv_mode == BLE_HCI_PRIVACY_NETWORK)) {
+                if (rl && (rl->rl_priv_mode == BLE_HCI_PRIVACY_NETWORK) &&
+                        ble_ll_resolv_irk_nonzero(rl->rl_peer_irk)) {
                     return 0;
                 }
             }