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/session.c

@@ -2,6 +2,7 @@
 #include <errno.h>
 #include <inttypes.h>
 #include <linux/kernel.h>
+#include <linux/zalloc.h>
 #include <traceevent/event-parse.h>
 #include <api/fs/fs.h>
 
@@ -18,7 +19,6 @@
 #include "session.h"
 #include "tool.h"
 #include "sort.h"
-#include "util.h"
 #include "cpumap.h"
 #include "perf_regs.h"
 #include "asm/bug.h"