block: merge disk_scan_partitions and blkdev_reread_part

mainline inclusion
from mainline-v5.17-rc1
commit e16e506c
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I6MQLP
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=e16e506ccd673a3a888a34f8f694698305840044



--------------------------------

Unify the functionality that implements a partition rescan for a
gendisk.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211122130625.1136848-6-hch@lst.de


Signed-off-by: Jens Axboe <axboe@kernel.dk>

Conflicts:
	block/blk.h
	block/genhd.c
	block/ioctl.c
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Jialin Zhang <zhangjialin11@huawei.com>