util/: use SPDX license and copyright headers

Signed-off-by: Leah Rowe <leah@libreboot.org>

util/nvmutil/Makefile

@@ -1,27 +1,5 @@
-#
-# Makefile for nvmutils
-#
-# Copyright (C) 2022 Leah Rowe <leah@libreboot.org>
-#
-# Permission is hereby granted, free of charge, to any person obtaining a
-# copy of this software and associated documentation files (the
-# "Software"), to deal in the Software without restriction, including
-# without limitation the rights to use, copy, modify, merge, publish,
-# distribute, sublicense, and/or sell copies of the Software, and to
-# permit persons to whom the Software is furnished to do so, subject to
-# the following conditions:
-#
-# The above copyright notice and this permission notice shall be included
-# in all copies or substantial portions of the Software.
-#
-# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
-# OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
-# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
-# IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
-# CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
-# TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
-# SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
-#
+# SPDX-License-Identifier: MIT
+# SPDX-FileCopyrightText: 2022 Leah Rowe <leah@libreboot.org>
 
 CC=cc
 CFLAGS=-Os -Wall -Wextra -Werror -pedantic

util/nvmutil/nvmutil.c

@@ -1,5 +1,5 @@
-/* Copyright (c) 2022, 2023 Leah Rowe <leah@libreboot.org> */
 /* SPDX-License-Identifier: MIT */
+/* SPDX-FileCopyrightText: 2022, 2023 Leah Rowe <leah@libreboot.org> */
 
 #include <sys/stat.h>