crc32: add spdx license tag

The crc.[ch] are missing the spdx tag.

Signed-off-by: Daniel Wagner <[email protected]>

Author: igaw

libnvme/src/nvme/crc32.c

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: LicenseRef-Gary-S-Brown-CRC32
 /*
  *  COPYRIGHT (C) 1986 Gary S. Brown.  You may use this program, or
  *  code or tables extracted from it, as desired without restriction.

libnvme/src/nvme/crc32.h

@@ -1,9 +1,10 @@
-#ifndef crc32_H
-#define crc32_H
+// SPDX-License-Identifier: LicenseRef-Gary-S-Brown-CRC32
+/*
+ * This file is part of libnvme.
+ */
+#pragma once
 
 #include <stdint.h>
 #include <stddef.h>
 
 uint32_t crc32(uint32_t crc, const void *buf, size_t len);
-
-#endif