[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/diskonchip.c

@@ -1666,7 +1666,7 @@ static int __init doc_probe(unsigned long physadr)
 	nand->ecc.mode		= NAND_ECC_HW_SYNDROME;
 	nand->ecc.size		= 512;
 	nand->ecc.bytes		= 6;
-	nand->options		= NAND_USE_FLASH_BBT | NAND_HWECC_SYNDROME;
+	nand->options		= NAND_USE_FLASH_BBT;
 
 	doc->physadr		= physadr;
 	doc->virtadr		= virtadr;

drivers/mtd/nand/edb7312.c

@@ -198,9 +198,6 @@ static void __exit ep7312_cleanup(void)
 	/* Release resources, unregister device */
 	nand_release(ap7312_mtd);
 
-	/* Free internal data buffer */
-	kfree(this->data_buf);
-
 	/* Free the MTD device structure */
 	kfree(ep7312_mtd);
 }