CVE-2021-47480

scsi: core: Put LLD module refcnt after SCSI device is released

In the Linux kernel, the following vulnerability has been resolved: scsi: core: Put LLD module refcnt after SCSI device is released SCSI host release is triggered when SCSI device is freed. We have to make sure that the low-level device driver module won't be unloaded before SCSI host instance is released because shost->hostt is required in the release handler. Make sure to put LLD module refcnt after SCSI device is released. Fixes a kernel panic of 'BUG: unable to handle page fault for address' reported by Changhui and Yi.