[SCSI] libsas: kill spurious sas_put_device

Holdover from a patch rework, prior to the addition of SAS_DEV_DESTROY
we were holding a reference while the destruct was pending in case the
domain was torn down before the desctruct event ran.  That case is
covered by SAS_DEV_DESTROY, and the sas_put_device() just corrupts freed
memory, or worse frees the memory while another agent holds a reference.

Signed-off-by: Maciej Trela <maciej.trela@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>