tools lib: Adopt zalloc()/zfree() from tools/perf

Eroding a bit more the tools/perf/util/util.h hodpodge header.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-natazosyn9rwjka25tvcnyi0@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/header.c

@@ -1,7 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
 #include <errno.h>
 #include <inttypes.h>
-#include "util.h"
 #include "string2.h"
 #include <sys/param.h>
 #include <sys/types.h>
@@ -15,6 +14,7 @@
 #include <linux/bitops.h>
 #include <linux/string.h>
 #include <linux/stringify.h>
+#include <linux/zalloc.h>
 #include <sys/stat.h>
 #include <sys/utsname.h>
 #include <linux/time64.h>