scsi: hisi_sas: Make phy index variable name consistent

We use "phy_id" to identify phy in the BIST code but the rest of code
always uses "phy_no". Change it for consistency.

Link: https://lore.kernel.org/r/1598958790-232272-5-git-send-email-john.garry@huawei.com


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