scsi: hisi_sas: use an general way to delay PHY work

Use an general way to do delay work for a PHY. Then it will be easier to add
new delayed work for a PHY in future.

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