sandbox: poweroff in efi_system_reset()

efi_system_reset() should exit if called with EFI_RESET_SHUTDOWN.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/sandbox/cpu/start.c b/arch/sandbox/cpu/start.c
index a74f5ec..13b0731 100644
--- a/arch/sandbox/cpu/start.c
+++ b/arch/sandbox/cpu/start.c
@@ -434,8 +434,10 @@
 		efi_status_t reset_status,
 		unsigned long data_size, void *reset_data)
 {
-	os_fd_restore();
-	os_relaunch(os_argv);
+	if (reset_type == EFI_RESET_SHUTDOWN)
+		sandbox_exit();
+	else
+		sandbox_reset();
 }
 
 void sandbox_reset(void)