[MTD] fix mtdconcat for subpage-write NAND

This allows the mtdconcat driver to work with NAND flash devices that
support sub-page writes.
Signed-off-by: NChris Paulson-Ellis <chris@edesix.com>
Signed-off-by: NDavid Woodhouse <dwmw2@infradead.org>

drivers/mtd/mtdconcat.c

@@ -726,6 +726,7 @@ struct mtd_info *mtd_concat_create(struct mtd_info *subdev[],	/* subdevices to c
 	concat->mtd.size = subdev[0]->size;
 	concat->mtd.erasesize = subdev[0]->erasesize;
 	concat->mtd.writesize = subdev[0]->writesize;
+	concat->mtd.subpage_sft = subdev[0]->subpage_sft;
 	concat->mtd.oobsize = subdev[0]->oobsize;
 	concat->mtd.oobavail = subdev[0]->oobavail;
 	if (subdev[0]->writev)