[SCSI] pm80xx: fix Adaptec 71605H hang

[SCSI] pm80xx: fix Adaptec 71605H hang

The IO command size is 128 bytes for these new controllers as opposed to 64
for the old 8001 controller.

The Adaptec out-of-tree driver did this correctly. After comparing the two
this turned out to be the crucial difference.

So don't hardcode the IO command size, instead use pm8001_ha->iomb_size as
that is the correct value for both old and new controllers.

Signed-off-by: Hans Verkuil <[email protected]>
Acked-by: Anand Kumar Santhanam <[email protected]>
Acked-by: Jack Wang <[email protected]>
Cc: [email protected]      # for v3.10 and up
Signed-off-by: James Bottomley <[email protected]>