scsi: scsi_debug: remove jiffies_to_timespec

There is no need to go through an intermediate timespec to convert to
ktime_t when we just want a simple multiplication. This gets rid of one
of the few users of jiffies_to_timespec, which I hope to remove as part
of the y2038 cleanup.
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de>
Acked-by: NDouglas Gilbert <dgilbert@interlog.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/scsi_debug.c

@@ -4085,10 +4085,7 @@ static int schedule_resp(struct scsi_cmnd *cmnd, struct sdebug_dev_info *devip,
 		ktime_t kt;
 
 		if (delta_jiff > 0) {
-			struct timespec ts;
-
-			jiffies_to_timespec(delta_jiff, &ts);
-			kt = ktime_set(ts.tv_sec, ts.tv_nsec);
+			kt = ns_to_ktime((u64)delta_jiff * (NSEC_PER_SEC / HZ));
 		} else
 			kt = sdebug_ndelay;
 		if (NULL == sd_dp) {