the push is modified as follows:

1. delete some junk files.
2. mqttclient added comments and updated to v1.0.2.
3. update README.md.
4. update the author's own server certificate.
5. minor changes to salof.

components/connectivity/mqttclient/common/log/salof.c

@@ -9,6 +9,8 @@
 
 #include "salof.h"
 
+#ifdef USE_LOG
+
 #ifndef SALOF_BUFF_SIZE
     #define     SALOF_BUFF_SIZE     (1024U)
 #endif 
@@ -104,5 +106,5 @@ void salof_task(void *parm)
 }
 #endif
 
-
+#endif