libs/libc/stdlib: remove BSD-4 clause

remove the advertising clause
3. All advertising materials mentioning features or use of this software must
display the following acknowledgement: This product includes software
developed by the University of California, Berkeley and its contributors.

permitted by Berkley amendment
https://ipira.berkeley.edu/sites/default/files/amendment_of_4-clause_bsd_software_license.pdf

following example from NETBSD and OPENBSD
NetBSD/src@eb7c159
openbsd/src@6580fee

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

Author: jerpelea

libs/libc/stdlib/lib_bsearch.c

@@ -12,11 +12,7 @@
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
- * 3. All advertising materials mentioning features or use of this software
- *    must display the following acknowledgement:
- *      This product includes software developed by the University of
- *      California, Berkeley and its contributors.
- * 4. Neither the name of the University nor the names of its contributors
+ * 3. Neither the name of the University nor the names of its contributors
  *    may be used to endorse or promote products derived from this software
  *    without specific prior written permission.
  *

libs/libc/stdlib/lib_qsort.c

@@ -18,11 +18,7 @@
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
- * 3. All advertising materials mentioning features or use of this software
- *    must display the following acknowledgement:
- *    This product includes software developed by the University of
- *    California, Berkeley and its contributors.
- * 4. Neither the name of the University nor the names of its contributors
+ * 3. Neither the name of the University nor the names of its contributors
  *    may be used to endorse or promote products derived from this software
  *    without specific prior written permission.
  *