block: fix device_add_disk() kobject_create_and_add() error handling

Commit 83cbce95 ("block: add error handling for device_add_disk /
add_disk") added error handling to device_add_disk(), however the goto
label for the kobject_create_and_add() failure did not set the return
value correctly, and so we can end up in a situation where
kobject_create_and_add() fails but we report success.

Fixes: 83cbce95 ("block: add error handling for device_add_disk / add_disk")
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211103164023.1384821-1-mcgrof@kernel.org


[axboe: fold in followup fix from Wu Bo <wubo40@huawei.com>]
Signed-off-by: Jens Axboe <axboe@kernel.dk>