perf bench: Fix misspellings using codespell

$ codespell ./tool/perf/bench
  tools/perf/bench/inject-buildid.c:375: tihs  ==> this

Fix a typo found by codespell.

Signed-off-by: Xiong Zhenwu <xiong.zhenwu@zte.com.cn>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20210305092212.204923-1-xiong.zhenwu@zte.com.cn
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/bench/inject-buildid.c

@@ -372,7 +372,7 @@ static int inject_build_id(struct bench_data *data, u64 *max_rss)
 			len += synthesize_flush(data);
 	}
 
-	/* tihs makes the child to finish */
+	/* this makes the child to finish */
 	close(data->input_pipe[1]);
 
 	wait4(data->pid, &status, 0, &rusage);