Add support for BBT without touching OOB area

[Sebastian Andrzej Siewior]

Without this patch (number three) NAND controllers which use complete OOB
area for ECC information can not use a BBT at all. The vendor bit is
gone after the first write and the flash BBT stores a marker in the OOB
area. The patch simply moves the marker into the data area.

The series contains:
- [PATCH 1/5] mtd/nand: use ALIGN where possible
- [PATCH 2/5] mtd/nand: pull in td into read_bbt()
clean up.

- [PATCH 3/5] mtd/nand: add support for BBT without OOB
adds the functionality.

- [PATCH 4/5] mtd/nand: introduce NAND_CREATE_EMPTY_BBT
NAND_CREATE_BBT creates a BBT based on vendor's informations (or something
else if specified). Without NAND_CREATE_BBT the BBT is written to flash
after the first bad block is found. This options enforces writting an
"empty" table.

- [PATCH 5/5] mtd/nandsim: add module param for BBT handling
Used for first testing.

Sebastian