scsi: pm8001: Remove unused declarations

Commit 4fcf812c ("[SCSI] libsas: export sas_alloc_task()") removed
these implementations but not the declarations.

Signed-off-by: Yue Haibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20230818124700.49724-1-yuehaibing@huawei.com


Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Acked-by: Jack Wang <jinpu.wang@ionos.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>