ssl_session: Define unconditionally the endpoint field

The endpoint field is needed to serialize/deserialize
a session in TLS 1.2 the same way it is needed in the
TLS 1.3 case: client specific fields that should not
be in the serialized version on server side if both
TLS client and server are enabled in the TLS library.

Signed-off-by: Ronald Cron <ronald.cron@arm.com>
diff --git a/include/mbedtls/ssl.h b/include/mbedtls/ssl.h
index 3629526..0be81af 100644
--- a/include/mbedtls/ssl.h
+++ b/include/mbedtls/ssl.h
@@ -1199,6 +1199,7 @@
      *  or resuming a session instead of the configured minor TLS version.
      */
     mbedtls_ssl_protocol_version MBEDTLS_PRIVATE(tls_version);
+    uint8_t MBEDTLS_PRIVATE(endpoint);          /*!< 0: client, 1: server */
 
 #if defined(MBEDTLS_HAVE_TIME)
     mbedtls_time_t MBEDTLS_PRIVATE(start);       /*!< start time of current session */
@@ -1228,7 +1229,6 @@
 #endif /* MBEDTLS_SSL_SESSION_TICKETS && MBEDTLS_SSL_CLI_C */
 
 #if defined(MBEDTLS_SSL_PROTO_TLS1_3) && defined(MBEDTLS_SSL_SESSION_TICKETS)
-    uint8_t MBEDTLS_PRIVATE(endpoint);          /*!< 0: client, 1: server */
     uint8_t MBEDTLS_PRIVATE(ticket_flags);      /*!< Ticket flags */
     uint32_t MBEDTLS_PRIVATE(ticket_age_add);               /*!< Randomly generated value used to obscure the age of the ticket */
     uint8_t MBEDTLS_PRIVATE(resumption_key_len);            /*!< resumption_key length */