scsi: remove unused kobj map for sd devie to avoid memleak

hulk inclusion
category: bugfix
bugzilla: 109288
CVE: NA

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After calling add_disk, we have register new kobj map for sd device,
then we can remove old unused kobj map which probed by sd_remove.

Signed-off-by: Yufen Yu <yuyufen@huawei.com>
Reviewed-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>