scsi: sd: fix missing put_disk() when device_add(&disk_dev) fails

scsi: sd: fix missing put_disk() when device_add(&disk_dev) fails

If device_add(&sdkp->disk_dev) fails, put_device() runs
scsi_disk_release(), which frees the scsi_disk but leaves the gendisk
referenced. The device_add_disk() error path in sd_probe() calls
put_disk(gd); call put_disk(gd) here to mirror that cleanup.

Fixes: 265dfe8ebbab ("scsi: sd: Free scsi_disk device via put_device()")
Cc: stable@vger.kernel.org
Reviewed-by: John Garry <john.g.garry@oracle.com>
Signed-off-by: Yang Xiuwei <yangxiuwei@kylinos.cn>
Link: https://patch.msgid.link/20260330014952.152776-1-yangxiuwei@kylinos.cn
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>