nimble/gap: Remove notification for update process timeout.

The connection parameter update process has a hard-coded 40-second timeout, but in reality, the time it takes to complete a connection parameter update will be around 6 * (connection interval) * (latency), which for some connection parameters will greatly exceed 40 seconds.  The timer was intended for the L2CAP update process, and is deleted once a response is received, so it needs to be there.  However, for the LL process there's no reason to inform the application of the timeout and thereby cause the connection to close.

nimble/host/src/ble_gap.c

@@ -1943,7 +1943,6 @@ ble_gap_update_timer(void)
         ble_hs_unlock();
 
         if (entry != NULL) {
-            ble_gap_update_notify(conn_handle, BLE_HS_ETIMEOUT);
             ble_gap_update_entry_free(entry);
         }
     } while (entry != NULL);