md: raid0: remove ->dev pointer from strip_zone structure

If we treat conf->devlist more like a 2 dimensional array,
we can get the devlist for a particular zone simply by indexing
that array, so we don't need to store the pointers to subarrays
in strip_zone.  This makes strip_zone smaller and so (hopefully)
searches faster.

Signed-of-by: NeilBrown <neilb@suse.de>

drivers/md/raid0.h

@@ -6,7 +6,6 @@ struct strip_zone
 	sector_t zone_end;	/* Start of the next zone (in sectors) */
 	sector_t dev_start;	/* Zone offset in real dev (in sectors) */
 	int nb_dev;		/* # of devices attached to the zone */
-	mdk_rdev_t **dev;	/* Devices attached to the zone */
 };
 
 struct raid0_private_data