[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>
diff --git a/drivers/mtd/nand/diskonchip.c b/drivers/mtd/nand/diskonchip.c
index 83af6f0..82262a4a 100644
--- a/drivers/mtd/nand/diskonchip.c
+++ b/drivers/mtd/nand/diskonchip.c
@@ -1666,7 +1666,7 @@
 	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;