perf trace: Use zalloc() to save initialization of syscall_stats

As most members of syscall_stats is set to 0 in thread__update_stats,
using zalloc() directly.
Signed-off-by: Shang XiaoJing <shangxiaojing@huawei.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220908021141.27134-2-shangxiaojing@huawei.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/builtin-trace.c

@@ -2173,13 +2173,10 @@ static void thread__update_stats(struct thread *thread, struct thread_trace *ttr
 
 	stats = inode->priv;
 	if (stats == NULL) {
-		stats = malloc(sizeof(*stats));
+		stats = zalloc(sizeof(*stats));
 		if (stats == NULL)
 			return;
 
-		stats->nr_failures = 0;
-		stats->max_errno   = 0;
-		stats->errnos	   = NULL;
 		init_stats(&stats->stats);
 		inode->priv = stats;
 	}