block: move the NEED_PART_SCAN flag to struct gendisk

mainline inclusion
from mainline-v5.10-rc1
commit 38430f08
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5ETAB


CVE: NA

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

We can only scan for partitions on the whole disk, so move the flag
from struct block_device to struct gendisk.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Conflicts:
	block/genhd.c
	drivers/ide/ide-gd.c
	fs/block_dev.c
	include/linux/blk_types.h

Signed-off-by: Luo Meng <luomeng12@huawei.com>
Reviewed-by: Jason Yan <yanaijie@huawei.com>
Signed-off-by: Laibin Qiu <qiulaibin@huawei.com>