[SCSI] scsi_debug: set resid to indicate no data-in when medium error

set resid to the requested data-in length when a MEDIUM ERROR is
simulated. This implies no valid data is returned in the data-in
buffer

Signed-off-by: Douglas Gilbert <[e-mail]>
Signed-off-by: James Bottomley <[e-mail]>

drivers/scsi/scsi_debug.c

···
 			devip->sense_buff[5] = (ret >> 8) & 0xff;
 			devip->sense_buff[6] = ret & 0xff;
 		}
+	        scsi_set_resid(SCpnt, scsi_bufflen(SCpnt));
 		return check_condition_result;
 	}