cleaned clang compile warnings

src/bacnet/basic/object/client/device-client.c

@@ -263,7 +263,7 @@ unsigned Device_Count(void)
 
 uint32_t Device_Index_To_Instance(unsigned index)
 {
-    index = index;
+    (void)index;
     return Object_Instance_Number;
 }
 

src/bacnet/basic/object/device.c

@@ -523,7 +523,7 @@ unsigned Device_Count(void)
 
 uint32_t Device_Index_To_Instance(unsigned index)
 {
-    index = index;
+    (void)index;
     return Object_Instance_Number;
 }
 

src/bacnet/basic/object/trendlog.c

@@ -1726,8 +1726,7 @@ void trend_log_timer(uint16_t uSeconds)
     int iCount = 0;
     time_t tNow = 0;
 
-    /* unused parameter */
-    uSeconds = uSeconds;
+    (void)uSeconds;
     /* use OS to get the current time */
     tNow = time(NULL);
     for (iCount = 0; iCount < MAX_TREND_LOGS; iCount++) {