perf test: Fix double word in comments

Delete the redundant word "then" in comments.
Signed-off-by: shaomin Deng <dengshaomin@cdjrlc.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20220807074753.7857-1-dengshaomin@cdjrlc.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/tests/perf-time-to-tsc.c

@@ -62,7 +62,7 @@ static int test__tsc_is_supported(struct test_suite *test __maybe_unused,
  * This function implements a test that checks that the conversion of perf time
  * to and from TSC is consistent with the order of events.  If the test passes
  * %0 is returned, otherwise %-1 is returned.  If TSC conversion is not
- * supported then then the test passes but " (not supported)" is printed.
+ * supported then the test passes but " (not supported)" is printed.
  */
 static int test__perf_time_to_tsc(struct test_suite *test __maybe_unused, int subtest __maybe_unused)
 {