netdevsim: remove unused sdev code

sdev.c code is merged into dev.c and is not used anymore.
it would be removed.
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/netdevsim/sdev.c

-// SPDX-License-Identifier: GPL-2.0
-/* Copyright (c) 2019 Mellanox Technologies. All rights reserved */
-
-#include <linux/debugfs.h>
-#include <linux/err.h>
-#include <linux/kernel.h>
-#include <linux/slab.h>
-
-#include "netdevsim.h"
-
-static struct dentry *nsim_sdev_ddir;
-
-static u32 nsim_sdev_id;
-
-struct netdevsim_shared_dev *nsim_sdev_get(struct netdevsim *joinns)
-{
-	struct netdevsim_shared_dev *sdev;
-	char sdev_ddir_name[10];
-	int err;
-
-	if (joinns) {
-		if (WARN_ON(!joinns->sdev))
-			return ERR_PTR(-EINVAL);
-		sdev = joinns->sdev;
-		sdev->refcnt++;
-		return sdev;
-	}
-
-	sdev = kzalloc(sizeof(*sdev), GFP_KERNEL);
-	if (!sdev)
-		return ERR_PTR(-ENOMEM);
-	sdev->refcnt = 1;
-	sdev->switch_id = nsim_sdev_id++;
-
-	sprintf(sdev_ddir_name, "%u", sdev->switch_id);
-	sdev->ddir = debugfs_create_dir(sdev_ddir_name, nsim_sdev_ddir);
-	if (IS_ERR_OR_NULL(sdev->ddir)) {
-		err = PTR_ERR_OR_ZERO(sdev->ddir) ?: -EINVAL;
-		goto err_sdev_free;
-	}
-
-	return sdev;
-
-err_sdev_free:
-	nsim_sdev_id--;
-	kfree(sdev);
-	return ERR_PTR(err);
-}
-
-void nsim_sdev_put(struct netdevsim_shared_dev *sdev)
-{
-	if (--sdev->refcnt)
-		return;
-	debugfs_remove_recursive(sdev->ddir);
-	kfree(sdev);
-}
-
-int nsim_sdev_init(void)
-{
-	nsim_sdev_ddir = debugfs_create_dir(DRV_NAME "_sdev", NULL);
-	if (IS_ERR_OR_NULL(nsim_sdev_ddir))
-		return -ENOMEM;
-	return 0;
-}
-
-void nsim_sdev_exit(void)
-{
-	debugfs_remove_recursive(nsim_sdev_ddir);
-}