[SCSI] qla2xxx: Use FW calculated residual count for underrun handling.

With ISP24XX and ISP54XX parts.

Signed-off-by: Andrew Vasquez <andrew.vasquez@qlogic.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
diff --git a/drivers/scsi/qla2xxx/qla_fw.h b/drivers/scsi/qla2xxx/qla_fw.h
index 1ee58ad..d2f58706 100644
--- a/drivers/scsi/qla2xxx/qla_fw.h
+++ b/drivers/scsi/qla2xxx/qla_fw.h
@@ -463,7 +463,7 @@
 	uint16_t comp_status;		/* Completion status. */
 	uint16_t ox_id;			/* OX_ID used by the firmware. */
 
-	uint32_t residual_len;		/* Residual transfer length. */
+	uint32_t residual_len;		/* FW calc residual transfer length. */
 
 	uint16_t reserved_1;
 	uint16_t state_flags;		/* State flags. */