Restore BOARD_ESP to handle board specific configurations

Author: pennam

src/AIoTC_Config.h

@@ -142,6 +142,7 @@
 #endif
 
 #if defined(ARDUINO_ESP8266_ESP12) || defined(ARDUINO_ARCH_ESP32) || defined(ESP8266) || defined(ESP32)
+  #define BOARD_ESP
   #define BOARD_HAS_SECRET_KEY
   #define HAS_TCP
 #endif

src/ArduinoIoTCloudTCP.h

@@ -29,7 +29,7 @@
 #ifdef BOARD_HAS_ECCX08
   #include "tls/BearSSLClient.h"
   #include "tls/utility/CryptoUtil.h"
-#elif defined(BOARD_HAS_SECRET_KEY)
+#elif defined(BOARD_ESP)
   #include <WiFiClientSecure.h>
 #elif defined(BOARD_HAS_SE050)
   #include "tls/utility/CryptoUtil.h"
@@ -143,15 +143,18 @@ class ArduinoIoTCloudTCP: public ArduinoIoTCloudClass
     ArduinoIoTCloudCertClass _cert;
     WiFiBearSSLClient _sslClient;
     CryptoUtil _crypto;
-    #elif defined(BOARD_HAS_SECRET_KEY)
+    #elif defined(BOARD_ESP)
     WiFiClientSecure _sslClient;
-    String _password;
     #elif defined(BOARD_HAS_SE050)
     ArduinoIoTCloudCertClass _cert;
     WiFiSSLSE050Client _sslClient;
     CryptoUtil _crypto;
     #endif
 
+    #if defined (BOARD_HAS_SECRET_KEY)
+    String _password;
+    #endif
+
     MqttClient _mqttClient;
 
     String _deviceTopicOut;