perf lock: Remove redundant word 'contention' in help message

Before:
  # perf lock -h

   Usage: perf lock [<options>] {record|report|script|info|contention|contention}

      -D, --dump-raw-trace  dump raw trace in ASCII
      -f, --force           don't complain, do it
      -i, --input <file>    input file name
      -v, --verbose         be more verbose (show symbol address, etc)
          --kallsyms <file>
                            kallsyms pathname
          --vmlinux <file>  vmlinux pathname

After:
  # perf lock -h

   Usage: perf lock [<options>] {record|report|script|info|contention}

      -D, --dump-raw-trace  dump raw trace in ASCII
      -f, --force           don't complain, do it
      -i, --input <file>    input file name
      -v, --verbose         be more verbose (show symbol address, etc)
          --kallsyms <file>
                            kallsyms pathname
          --vmlinux <file>  vmlinux pathname

Fixes: 528b9cab ("perf lock: Add 'contention' subcommand")
Signed-off-by: Yang Jihong <yangjihong1@huawei.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220908014854.151203-1-yangjihong1@huawei.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/builtin-lock.c

@@ -1874,8 +1874,7 @@ int cmd_lock(int argc, const char **argv)
 		NULL
 	};
 	const char *const lock_subcommands[] = { "record", "report", "script",
-						 "info", "contention",
-						 "contention", NULL };
+						 "info", "contention", NULL };
 	const char *lock_usage[] = {
 		NULL,
 		NULL