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/builtin-diff.c

@@ -16,12 +16,12 @@
 #include "util/tool.h"
 #include "util/sort.h"
 #include "util/symbol.h"
-#include "util/util.h"
 #include "util/data.h"
 #include "util/config.h"
 #include "util/time-utils.h"
 #include "util/annotate.h"
 #include "util/map.h"
+#include <linux/zalloc.h>
 
 #include <errno.h>
 #include <inttypes.h>