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/I6MRB5
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:
 - comit f0b870df ("block: remove (__)blkdev_reread_part as an
 exported API") is not backported, and this patch doesn't remove
 (__)blkdev_reread_part apis as well.
 - commit b98bcd9e ("block: reopen the device in blkdev_reread_part")
 is not backported, this patch switch blkdev_reread_part() to
 disk_scan_partitions() directly, which will reopen the device.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Yongqiang Liu <liuyongqiang13@huawei.com>