perf trace: Fix IS_ERR() vs NULL check bug

[ Upstream commit 96f202e ]

The alloc_syscall_stats() function always returns an error pointer
(ERR_PTR) on failure.

So replace NULL check with IS_ERR() check after calling
delete_syscall_stats() function.

Fixes: ef2da61 ("perf trace: Convert syscall_stats to hashmap")
Signed-off-by: wangguangju <wangguangju@hygon.cn>
Reviewed-by: Howard Chu <howardchu95@gmail.com>
Acked-by: Ian Rogers <irogers@google.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

Author: wangguangju

tools/perf/builtin-trace.c

@@ -1573,7 +1573,7 @@ static void delete_syscall_stats(struct hashmap *syscall_stats)
 	struct hashmap_entry *pos;
 	size_t bkt;
 
-	if (syscall_stats == NULL)
+	if (IS_ERR(syscall_stats))
 		return;
 
 	hashmap__for_each_entry(syscall_stats, pos, bkt)