mtd: nand: pxa3xx: Use ECC strength and step size devicetree binding

This commit adds support for the user to specify the ECC strength
and step size through the devicetree. We keep the previous behavior,
when there is no DT parameter provided.

Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

include/linux/platform_data/mtd-nand-pxa3xx.h

@@ -58,6 +58,9 @@ struct pxa3xx_nand_platform_data {
 	/* use an flash-based bad block table */
 	bool	flash_bbt;
 
+	/* requested ECC strength and ECC step size */
+	int ecc_strength, ecc_step_size;
+
 	const struct mtd_partition		*parts[NUM_CHIP_SELECT];
 	unsigned int				nr_parts[NUM_CHIP_SELECT];