scsi: sr: Add error handling support for add_disk()

mainline inclusion
from mainline-v5.16-rc1
commit e9d658c2
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I81XCK

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=e9d658c2175b95a8f091b12ddefb271683aeacd9

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

We never checked for errors on add_disk() as this function returned
void. Now that this is fixed, use the shiny new error handling.

Just put the cdrom kref and have the unwinding be done by
sr_kref_release().

Link: https://lore.kernel.org/r/20211015233028.2167651-3-mcgrof@kernel.org


Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Zhong Jinghua <zhongjinghua@huawei.com>
Signed-off-by: Li Nan <linan122@huawei.com>