spl: nand: initialize writesize for am335x

Initialize mtd->writesize in nand_init() as otherwise
nand_page_size() returns 0 and this affects NAND read
operations.

Signed-off-by: Yegor Yefremov <yegorslists@googlemail.com>

drivers/mtd/nand/raw/am335x_spl_bch.c

diff --git a/drivers/mtd/nand/raw/am335x_spl_bch.c b/drivers/mtd/nand/raw/am335x_spl_bch.c
index 4b50f35..a77206d 100644
--- a/drivers/mtd/nand/raw/am335x_spl_bch.c
+++ b/drivers/mtd/nand/raw/am335x_spl_bch.c
@@ -212,6 +212,8 @@
 	if (nand_chip.select_chip)
 		nand_chip.select_chip(mtd, 0);
 
+	mtd->writesize = CONFIG_SYS_NAND_PAGE_SIZE;
+
 	/* NAND chip may require reset after power-on */
 	nand_command(0, 0, 0, NAND_CMD_RESET);
 }