[Fix] Type for pointers operations (#550)

* fix type for pointers operations in some places: size_t -> portPOINTER_SIZE_TYPE

* fix pointer arithmetics

* fix xAddress type

portable/MemMang/heap_2.c

@@ -353,7 +353,7 @@ static void prvHeapInit( void ) /* PRIVILEGED_FUNCTION */
 
     /* To start with there is a single free block that is sized to take up the
      * entire heap space. */
-    pxFirstFreeBlock = ( void * ) pucAlignedHeap;
+    pxFirstFreeBlock = ( BlockLink_t * ) pucAlignedHeap;
     pxFirstFreeBlock->xBlockSize = configADJUSTED_HEAP_SIZE;
     pxFirstFreeBlock->pxNextFreeBlock = &xEnd;
 }