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 <[e-mail]>
Cc: Alexander Shishkin <[e-mail]>
Cc: Ian Rogers <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Mark Rutland <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Link: http://lore.kernel.org/lkml/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/bench/inject-buildid.c

···
 			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);