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/call-path.c

@@ -6,8 +6,9 @@
 
 #include <linux/rbtree.h>
 #include <linux/list.h>
+#include <linux/zalloc.h>
+#include <stdlib.h>
 
-#include "util.h"
 #include "call-path.h"
 
 static void call_path__init(struct call_path *cp, struct call_path *parent,