[MTD] NAND modularize ECC

First step of modularizing ECC support.
- Move ECC related functionality into a seperate embedded data structure
- Get rid of the hardware dependend constants to simplify new ECC models

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

drivers/mtd/nand/au1550nd.c

@@ -578,7 +578,7 @@ static int __init au1xxx_nand_init(void)
 
 	/* 30 us command delay time */
 	this->chip_delay = 30;
-	this->eccmode = NAND_ECC_SOFT;
+	this->ecc.mode = NAND_ECC_SOFT;
 
 	this->options = NAND_NO_AUTOINCR;