test: fix mi.c kernel-doc-check warning

To fix the warning message below.
  test/mi.c:3: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst

Signed-off-by: Tokunori Ikegami <[email protected]>

Author: ikegami-t

libnvme/test/mi.c

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: LGPL-2.1-or-later
-/**
+/*
  * This file is part of libnvme.
  * Copyright (c) 2022 Code Construct
  */