[MTD] NAND modularize write function

Modularize the write function and reorganaize the internal buffer
management. Remove obsolete chip options and fixup all affected
users.

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

drivers/mtd/nand/nand_bbt.c

@@ -666,7 +666,7 @@ static inline int nand_memory_bbt(struct mtd_info *mtd, struct nand_bbt_descr *b
 	struct nand_chip *this = mtd->priv;
 
 	bd->options &= ~NAND_BBT_SCANEMPTY;
-	return create_bbt(mtd, this->data_buf, bd, -1);
+	return create_bbt(mtd, this->buffers.databuf, bd, -1);
 }
 
 /**