writeback: remove obsolete macro EXPIRE_DIRTY_ATIME

EXPIRE_DIRTY_ATIME is not used anymore. Remove it.
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20221210101042.2012931-1-linmiaohe@huawei.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

fs/fs-writeback.c

@@ -1358,8 +1358,6 @@ static bool inode_dirtied_after(struct inode *inode, unsigned long t)
 	return ret;
 }
 
-#define EXPIRE_DIRTY_ATIME 0x0001
-
 /*
  * Move expired (dirtied before dirtied_before) dirty inodes from
  * @delaying_queue to @dispatch_queue.