!667 解决taskCB未定义以及初始化的问题

Merge pull request !667 from 夏不白/cherry-pick-1648781865

arch/arm/arm9/gcc/los_context.c

@@ -76,6 +76,7 @@ LITE_OS_SEC_TEXT_MINOR VOID ArchSysExit(VOID)
 LITE_OS_SEC_TEXT_INIT VOID *ArchTskStackInit(UINT32 taskID, UINT32 stackSize, VOID *topStack)
 {
     TaskContext *context = (TaskContext *)((UINTPTR)topStack + stackSize - sizeof(TaskContext));
+    LosTaskCB *taskCB = OS_TCB_FROM_TID(taskID);
 
     context->r0 = taskID;
     context->r1 = 0x01010101L;