libs/libc/stdlib: migrate to SPDX identifier

Most tools used for compliance and SBOM generation use SPDX identifiers
This change brings us a step closer to an easy SBOM generation.

Signed-off-by: Alin Jerpelea <[email protected]>

Author: jerpelea

libs/libc/stdlib/lib_bsearch.c

@@ -1,8 +1,10 @@
 /****************************************************************************
  * libs/libc/stdlib/lib_bsearch.c
  *
- *   Copyright (c) 1990, 1993
- *   The Regents of the University of California.  All rights reserved.
+ * SPDX-License-Identifier: BSD-3-Clause
+ * SPDX-FileCopyrightText: 1990 The Regents of the University of California.
+ * SPDX-FileCopyrightText: 1993 The Regents of the University of California.
+ * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions

libs/libc/stdlib/lib_qsort.c

@@ -1,13 +1,12 @@
 /****************************************************************************
  * libs/libc/stdlib/lib_qsort.c
  *
- *   Copyright (C) 2007, 2009, 2011 Gregory Nutt. All rights reserved.
- *   Author: Gregory Nutt <[email protected]>
- *
- * Leveraged from:
- *
- *  Copyright (c) 1992, 1993
- *  The Regents of the University of California.  All rights reserved.
+ * SPDX-License-Identifier: BSD-3-Clause
+ * SPDX-FileCopyrightText: 2007, 2009, 2011 Gregory Nutt.
+ * SPDX-FileCopyrightText: 1993 The Regents of the University of California.
+ * SPDX-FileCopyrightText: 1990 The Regents of the University of California.
+ * SPDX-FileContributor: Gregory Nutt <[email protected]>
+ * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions