ssl_client.c: Adapt ciphersuite writing to TLS 1.2 case

Signed-off-by: Ronald Cron <ronald.cron@arm.com>
diff --git a/library/ssl_misc.h b/library/ssl_misc.h
index f3f5f8d..2586c6d 100644
--- a/library/ssl_misc.h
+++ b/library/ssl_misc.h
@@ -1299,6 +1299,9 @@
 #if defined(MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED)
 int mbedtls_ssl_psk_derive_premaster( mbedtls_ssl_context *ssl,
                                       mbedtls_key_exchange_type_t key_ex );
+#if defined(MBEDTLS_SSL_CLI_C) && defined(MBEDTLS_SSL_PROTO_TLS1_2)
+int mbedtls_ssl_conf_has_static_psk( mbedtls_ssl_config const *conf );
+#endif
 
 /**
  * Get the first defined PSK by order of precedence: