Update main.c

Remove unused variable from the MingW demo's main.c file.

FreeRTOS/Demo/WIN32-MingW/main.c

@@ -351,7 +351,6 @@ purposes. */
 static uint8_t ucHeap[ configTOTAL_HEAP_SIZE ];
 volatile uint32_t ulAdditionalOffset = 19; /* Just to prevent 'condition is always true' warnings in configASSERT(). */
 HeapStats_t xHeapStats;
-const HeapStats_t xZeroHeapStats = { 0 };
 const HeapRegion_t xHeapRegions[] =
 {
 	/* Start address with dummy offsets						Size */