add mqttclient to the component, and add fire stm32f429 board demo.

components/connectivity/mqttclient/platform/TencentOS-tiny/platform_thread.h

@@ -0,0 +1,25 @@
+/*
+ * @Author: jiejie
+ * @Github: https://github.com/jiejieTop
+ * @Date: 2019-12-15 18:31:44
+ * @LastEditTime : 2020-01-08 20:24:17
+ * @Description: the code belongs to jiejie, please keep the author information and source code according to the license.
+ */
+#ifndef _PLATFORM_THREAD_H_
+#define _PLATFORM_THREAD_H_
+
+#include "tos_k.h"
+
+typedef struct platform_thread {
+    k_task_t thread;
+} platform_thread_t;
+
+platform_thread_t *platform_thread_init( const char *name,
+                                        void (*entry)(void *),
+                                        void * const param,
+                                        unsigned int stack_size,
+                                        unsigned int priority,
+                                        unsigned int tick);
+void platform_thread_destroy(platform_thread_t* thread);
+
+#endif