tls: Change some external symbols from Mbed TLS

In Mbed TLS:
    commit eccd88871767e2fba5f3a079cfdfcb77c376cf20
    Author: Gilles Peskine <[email protected]>
    Date:   Tue Mar 10 12:19:08 2020 +0100

        Rename identifiers containing double-underscore

changes the name of a symbol we use.  As part of upgrading to newer
versions of Mbed TLS, change the name of the symbol we use.

A better fix would be to not use this symbol at all, and perhaps define
our own symbol the same way this internal symbol is defined within the
library.

Signed-off-by: David Brown <[email protected]>

Author: d3zd3z

samples/net/cloud/google_iot_mqtt/src/protocol.c

@@ -62,7 +62,7 @@ static sec_tag_t m_sec_tags[] = {
 #if defined(MBEDTLS_X509_CRT_PARSE_C)
 		1,
 #endif
-#if defined(MBEDTLS_KEY_EXCHANGE__SOME__PSK_ENABLED)
+#if defined(MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED)
 		APP_PSK_TAG,
 #endif
 };

samples/net/mqtt_publisher/src/main.c

@@ -67,7 +67,7 @@ static APP_DMEM sec_tag_t m_sec_tags[] = {
 #if defined(MBEDTLS_X509_CRT_PARSE_C) || defined(CONFIG_NET_SOCKETS_OFFLOAD)
 		APP_CA_CERT_TAG,
 #endif
-#if defined(MBEDTLS_KEY_EXCHANGE__SOME__PSK_ENABLED)
+#if defined(MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED)
 		APP_PSK_TAG,
 #endif
 };
@@ -85,7 +85,7 @@ static int tls_init(void)
 	}
 #endif
 
-#if defined(MBEDTLS_KEY_EXCHANGE__SOME__PSK_ENABLED)
+#if defined(MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED)
 	err = tls_credential_add(APP_PSK_TAG, TLS_CREDENTIAL_PSK,
 				 client_psk, sizeof(client_psk));
 	if (err < 0) {

samples/net/mqtt_publisher/src/test_certs.h

@@ -127,7 +127,7 @@ static const unsigned char ca_certificate[] = {
 };
 #endif /* MBEDTLS_X509_CRT_PARSE_C */
 
-#if defined(MBEDTLS_KEY_EXCHANGE__SOME__PSK_ENABLED)
+#if defined(MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED)
 /* Avoid leading zero in psk because there's a potential issue of mosquitto
  * that leading zero of psk will be skipped and it leads to TLS handshake
  * failure

subsys/net/lib/sockets/sockets_tls.c

@@ -731,7 +731,7 @@ static int tls_set_psk(struct tls_context *tls,
 		       struct tls_credential *psk,
 		       struct tls_credential *psk_id)
 {
-#if defined(MBEDTLS_KEY_EXCHANGE__SOME__PSK_ENABLED)
+#if defined(MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED)
 	int err = mbedtls_ssl_conf_psk(&tls->config,
 				       psk->buf, psk->len,
 				       (const unsigned char *)psk_id->buf,