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>
diff --git a/tools/perf/util/thread.c b/tools/perf/util/thread.c
index 3e29a4e..bbfb9c7 100644
--- a/tools/perf/util/thread.c
+++ b/tools/perf/util/thread.c
@@ -5,10 +5,10 @@
 #include <stdio.h>
 #include <string.h>
 #include <linux/kernel.h>
+#include <linux/zalloc.h>
 #include "session.h"
 #include "thread.h"
 #include "thread-stack.h"
-#include "util.h"
 #include "debug.h"
 #include "namespaces.h"
 #include "comm.h"