scsi: hisi_sas: Stop converting a bool into a bool

The !! operator on a bool is pointless, so remove an example in
hisi_sas_rescan_topology().

Link: https://lore.kernel.org/r/1573551059-107873-5-git-send-email-john.garry@huawei.com


Signed-off-by: John Garry <john.garry@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>