perf tools: Ditch rtrim(), use strim() from tools/lib

Cleaning up a bit more tools/perf/util/ by using things we got from the
kernel and have in tools/lib/

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-7hluuoveryoicvkclshzjf1k@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index 38dc0c6..8139a1f 100644
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -395,7 +395,7 @@ static int perf_pmu__new_alias(struct list_head *list, char *dir, char *name, FI
 	buf[ret] = 0;
 
 	/* Remove trailing newline from sysfs file */
-	rtrim(buf);
+	strim(buf);
 
 	return __perf_pmu__new_alias(list, dir, name, NULL, buf, NULL, NULL, NULL,
 				     NULL, NULL, NULL);