[SCSI] qla2xxx: Prep zero-length BSG data-transfer requests.

During command failure/non-recognition, the upper-layer
FC-transport expects the drivers to set
job-reply->reply_payload_rcv_len.  Do this in a consistent manner
to avoid duplication.

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