esp_tls: Added getter function for esp_tls ssl ctx.

components/esp-tls/private_include/esp_tls_mbedtls.h

@@ -56,6 +56,11 @@ static inline void esp_mbedtls_net_init(esp_tls_t *tls)
     mbedtls_net_init(&tls->server_fd);
 }
 
+/**
+ * Return ssl context for mbedTLS stack
+ */
+void *esp_mbedtls_get_ssl_context(esp_tls_t *tls);
+
 #ifdef CONFIG_ESP_TLS_SERVER
 /**
  * Internal Callback for set_server_config