[SCSI] scsi_transport_spi: fix domain validation failure from incorrect width setting

Domain Validation in the SPI transport class is failing on boxes with
damaged cables (and failing to the extent that the box hangs).  The
problem is that the first test it does is a cable integrity test for
wide transfers and if this fails, it turns the wide bit off.  The
problem is that the next set of tests it does turns wide back on
again, with the result that it runs through the entirety of DV with a
known bad setting and then hangs the system.

The attached patch fixes the problem by physically nailing the wide
setting to what it deduces it should be for the whole of Domain
Validation.

Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>