mtd: {nand,spi-nor}: assign MTD of_node

We should pass along our flash DT node to the MTD layer, so it can set
up ofpart for us.

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com>

drivers/mtd/spi-nor/spi-nor.c

@@ -1258,6 +1258,7 @@ int spi_nor_scan(struct spi_nor *nor, const char *name, enum read_mode mode)
 		mtd->flags |= MTD_NO_ERASE;
 
 	mtd->dev.parent = dev;
+	mtd_set_of_node(mtd, np);
 	nor->page_size = info->page_size;
 	mtd->writebufsize = nor->page_size;