perf sched replay: Fix -r/--repeat command line option for infinity

Currently, the -r/--repeat option accepts values from 0 and complains
for -1. The help section specifies:
-r, --repeat <n> repeat the workload replay N times (-1: infinite)

The -r -1 option raises an error because replay_repeat is defined as
an unsigned int.

In the current implementation, the workload is repeated n times when
-r <n> is used, except when n is 0.

When -r is set to 0, the workload is also repeated once. This happens
because when -r=0, the run_one_test function is not called. (Note that
mutex unlocking, which is essential for child threads spawned to emulate
the workload, happens in run_one_test.) However, mutex unlocking is
still performed in the destroy_tasks function. Thus, -r=0 results in the
workload running once coincidentally.

To clarify and maintain the existing logic for -r >= 1 (which runs the
workload the specified number of times) and to fix the issue with infinite
runs, make -r=0 perform an infinite run.

Reviewed-by: James Clark <[e-mail]>
Signed-off-by: Madadi Vineeth Reddy <[e-mail]>
Cc: Athira Rajeev <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Namhyung Kim <[e-mail]>

tools/perf/Documentation/perf-sched.txt

···
 --state::
 	Show task state when it switched out.
 
+OPTIONS for 'perf sched replay'
+------------------------------
+
+-r::
+--repeat <n>::
+	repeat the workload n times (0: infinite). Default is 10.
+
 SEE ALSO
 --------
 linkperf:perf-record[1]

tools/perf/builtin-sched.c

···
 	sched->thread_funcs_exit = false;
 	create_tasks(sched);
 	printf("------------------------------------------------------------\n");
+	if (sched->replay_repeat == 0)
+		sched->replay_repeat = UINT_MAX;
+
 	for (i = 0; i < sched->replay_repeat; i++)
 		run_one_test(sched);
 
···
 	};
 	const struct option replay_options[] = {
 	OPT_UINTEGER('r', "repeat", &sched.replay_repeat,
-		     "repeat the workload replay N times (-1: infinite)"),
+		     "repeat the workload replay N times (0: infinite)"),
 	OPT_PARENT(sched_options)
 	};
 	const struct option map_options[] = {