sched/clock: remove unused function clock_dow() (dow:day of week)

1. This file is not included in the makefile.
2. This feature should be replaced with mktime().

Signed-off-by: chao an <anchao.archer@bytedance.com>

.github/CODEOWNERS

@@ -22287,7 +22287,6 @@ sched/addrenv/addrenv.c ville.juven@unikie.com hujun5@xiaomi.com alin.jerpelea@s
 sched/clock/clock.c alin.jerpelea@sony.com xiaoxiang@xiaomi.com
 sched/clock/clock.h alin.jerpelea@sony.com xiaoxiang@xiaomi.com jussi.kivilinna@haltian.com jpa@git.mail.kapsi.fi
 sched/clock/clock_adjtime.c jpa@git.mail.kapsi.fi michallenc@seznam.cz hujun5@xiaomi.com anchao@xiaomi.com ouyangxiangzhen@xiaomi.com
-sched/clock/clock_dow.c alin.jerpelea@sony.com gustavo.nihei@espressif.com arjun@zglue.com
 sched/clock/clock_gettime.c liguiding1@xiaomi.com guoshichao@xiaomi.com xiaoxiang@xiaomi.com alin.jerpelea@sony.com
 sched/clock/clock_initialize.c jussi.kivilinna@haltian.com xiaoxiang@xiaomi.com michallenc@seznam.cz jpa@git.mail.kapsi.fi
 sched/clock/clock_perf.c yinshengkai@xiaomi.com ouyangxiangzhen@xiaomi.com liguiding1@xiaomi.com alin.jerpelea@sony.com

sched/clock/clock_dow.c

@@ -1,75 +0,0 @@
-/****************************************************************************
- * sched/clock/clock_dow.c
- *
- * SPDX-License-Identifier: Apache-2.0
- *
- * Licensed to the Apache Software Foundation (ASF) under one or more
- * contributor license agreements.  See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.  The
- * ASF licenses this file to you under the Apache License, Version 2.0 (the
- * "License"); you may not use this file except in compliance with the
- * License.  You may obtain a copy of the License at
- *
- *   http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
- * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
- * License for the specific language governing permissions and limitations
- * under the License.
- *
- ****************************************************************************/
-
-/****************************************************************************
- * Included Files
- ****************************************************************************/
-
-#include <nuttx/config.h>
-
-#include <stdint.h>
-
-#include <nuttx/clock.h>
-
-#include "clock/clock.h"
-
-/****************************************************************************
- * Private Data
- ****************************************************************************/
-
-/* 23 * (month + 1) / 9, month = 0..11 */
-
-static const uint8_t g_lookup[12] =
-{
-  2, 5, 7, 10, 12, 15, 17, 20, 23, 25, 28, 30
-};
-
-/****************************************************************************
- * Public Functions
- ****************************************************************************/
-
-/****************************************************************************
- * Name: clock_dow
- *
- * Description:
- *   Calculate the day of week (DOW) from they year month and day.  Based on
- *   an algorithm published in 1990 by Michael Keith and Tom Craver with some
- *   tweaks to handle months in the range 0-11.
- *
- * Input Parameters:
- *   year  - year (e.g., 1988)
- *   month - 0 through 11
- *   day   - 1 through 31
- *
- * Returned Value:
- *   The day of the week as days since Sunday: 0 = Sunday, 1 = Monday, etc.
- *
- * Assumptions:
- *
- ****************************************************************************/
-
-int clock_dow(int year, int month, int day)
-{
-  day += month < 2 ? year-- : year - 2;
-  return ((int)g_lookup[month] + day + 4 + year / 4 -
-           year / 100 + year / 400) % 7;
-}