ata: SATL compliance for Inquiry Product Revision

The SCSI-to-ATA Translation standard says to use data words 25 and 26
unless they are spaces. For devices that use these words in the firmware
field, they are generally more useful anyway.

Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Tejun Heo <tj@kernel.org>