[SCSI] qla2xxx: T10 DIF - Handle uninitalized sectors.

Driver needs to update protection bytes for uninitialized sectors as they are
not DMA-d.

Signed-off-by: Arun Easi <arun.easi@qlogic.com>
Reviewed-by: Andrew Vasquez <andrew.vasquez@qlogic.com>
Signed-off-by: Chad Dupuis <chad.dupuis@qlogic.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>