[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/sr.c b/drivers/scsi/sr.c
index 45b66b9..e7fa3ca 100644
--- a/drivers/scsi/sr.c
+++ b/drivers/scsi/sr.c
@@ -177,7 +177,7 @@
 	do {
 		the_result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL,
 					      0, sshdr, SR_TIMEOUT,
-					      retries--);
+					      retries--, NULL);
 		if (scsi_sense_valid(sshdr) &&
 		    sshdr->sense_key == UNIT_ATTENTION)
 			sdev->changed = 1;
@@ -681,7 +681,7 @@
 		/* Do the command and wait.. */
 		the_result = scsi_execute_req(cd->device, cmd, DMA_FROM_DEVICE,
 					      buffer, sizeof(buffer), NULL,
-					      SR_TIMEOUT, MAX_RETRIES);
+					      SR_TIMEOUT, MAX_RETRIES, NULL);
 
 		retries--;