add reboot cmd for arm and delete shutcmd

arch/arm/shared/prepare_ahwstack.c

@@ -16,6 +16,7 @@
 #include "svc_handle.h"
 #include "stm32f4xx.h"
 #include <board.h>
+#include <shell.h>
 
 #if (defined ( __GNUC__ ) && defined ( __VFP_FP__ ) && !defined(__SOFTFP__))
 #define USE_FPU   1
@@ -410,13 +411,8 @@ void MemFaultHandle(uintptr_t *sp)
       
 }
 
-void ShutdownCpu(void)
-{
-    KPrintf("shutdown...\n");
-    CHECK(0);
-}
-
 __attribute__((weak)) void HwCpuReset(void)
 {
     SCB_AIRCR = SCB_RESET_VALUE;
 }
+SHELL_EXPORT_CMD(SHELL_CMD_PERMISSION(0)|SHELL_CMD_TYPE(SHELL_TYPE_CMD_FUNC)|SHELL_CMD_PARAM_NUM(0), Reboot, HwCpuReset, reset machine );