[SCSI] add residual argument to scsi_execute and scsi_execute_req

scsi_execute() and scsi_execute_req() discard the residual length
information. Some callers need it. This adds residual argument
(optional) to scsi_execute and scsi_execute_req.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
diff --git a/drivers/scsi/ch.c b/drivers/scsi/ch.c
index 88ecf94..af97254 100644
--- a/drivers/scsi/ch.c
+++ b/drivers/scsi/ch.c
@@ -190,7 +190,7 @@
 
         result = scsi_execute_req(ch->device, cmd, direction, buffer,
 				  buflength, &sshdr, timeout * HZ,
-				  MAX_RETRIES);
+				  MAX_RETRIES, NULL);
 
 	dprintk("result: 0x%x\n",result);
 	if (driver_byte(result) & DRIVER_SENSE) {