pxa3xx_nand: reset read buffer before reading

Initialize the read buffer content to 0xFF.
Signed-off-by: NHaojian Zhuang <haojian.zhuang@marvell.com>
Signed-off-by: NEric Miao <eric.y.miao@gmail.com>

drivers/mtd/nand/pxa3xx_nand.c

@@ -670,6 +670,7 @@ static void pxa3xx_nand_cmdfunc(struct mtd_info *mtd, unsigned command,
 		/* disable HW ECC to get all the OOB data */
 		info->buf_count = mtd->writesize + mtd->oobsize;
 		info->buf_start = mtd->writesize + column;
+		memset(info->data_buff, 0xFF, info->buf_count);
 
 		if (prepare_read_prog_cmd(info, cmdset->read1, column, page_addr))
 			break;