md: raid0: Represent device offset in sectors.

Rename zone->dev_offset to zone->dev_start to make sure all users
have been converted.

Signed-off-by: Andre Noll <maan@systemlinux.org>
Signed-off-by: NeilBrown <neilb@suse.de>
diff --git a/include/linux/raid/raid0.h b/include/linux/raid/raid0.h
index 1b2dda0..61c3d29 100644
--- a/include/linux/raid/raid0.h
+++ b/include/linux/raid/raid0.h
@@ -6,7 +6,7 @@
 struct strip_zone
 {
 	sector_t zone_offset;	/* Zone offset in md_dev */
-	sector_t dev_offset;	/* Zone offset in real dev */
+	sector_t dev_start;	/* Zone offset in real dev (in sectors) */
 	sector_t size;		/* Zone size */
 	int nb_dev;		/* # of devices attached to the zone */
 	mdk_rdev_t **dev;	/* Devices attached to the zone */