MTD: atmel_nand: support for software BCH ECC

Add possible to use software BCH ECC for atmel nand driver

Signed-off-by: Bo Shen <voice.shen@gmail.com>
diff --git a/drivers/mtd/nand/atmel_nand.c b/drivers/mtd/nand/atmel_nand.c
index da83f06..10011c6 100644
--- a/drivers/mtd/nand/atmel_nand.c
+++ b/drivers/mtd/nand/atmel_nand.c
@@ -1178,7 +1178,11 @@
 	mtd->priv = nand;
 	nand->IO_ADDR_R = nand->IO_ADDR_W = (void  __iomem *)base_addr;
 
+#ifdef CONFIG_NAND_ECC_BCH
+	nand->ecc.mode = NAND_ECC_SOFT_BCH;
+#else
 	nand->ecc.mode = NAND_ECC_SOFT;
+#endif
 #ifdef CONFIG_SYS_NAND_DBW_16
 	nand->options = NAND_BUSWIDTH_16;
 #endif