[bsp][stm32h743-nucleo] fix the bug of HEAP_BEGIN define.
#define EXT_SDRAM_END (EXT_SDRAM_BEGIN + EXT_SDRAM_SIZE)
// </e>
-#ifdef __CC_ARM
-extern int Image$$RW_IRAM1$$ZI$$Limit;
-#define HEAP_BEGIN (&Image$$RW_IRAM1$$ZI$$Limit)
-#elif __ICCARM__
-#pragma section="HEAP"
-#define HEAP_BEGIN (__segment_end("HEAP"))
-#else
-extern int __bss_end;
-#define HEAP_BEGIN (&__bss_end)
-#endif
+
+#define HEAP_BEGIN 0x24000000
// <o> Internal SRAM memory size[Kbytes] <8-64>
// <i>Default: 64
