UBI: bugfix: calculate data offset properly

Data offset is VID header offset + VID header size aligned to
the min. I/O unit size up.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

drivers/mtd/ubi/build.c

@@ -562,7 +562,7 @@ static int io_init(struct ubi_device *ubi)
 	}
 
 	/* Similar for the data offset */
-	ubi->leb_start = ubi->vid_hdr_offset + ubi->vid_hdr_alsize;
+	ubi->leb_start = ubi->vid_hdr_offset + UBI_EC_HDR_SIZE;
 	ubi->leb_start = ALIGN(ubi->leb_start, ubi->min_io_size);
 
 	dbg_msg("vid_hdr_offset   %d", ubi->vid_hdr_offset);