mtd: rawnand: Support bad block markers in first, second or last page

Currently supported bad block marker positions within the block are:
* in first page only
* in last page only
* in first or second page

Some ESMT NANDs are known to have been shipped by the manufacturer
with bad block markers in the first or last page, instead of the
first or second page.

Also the datasheets for Cypress/Spansion/AMD NANDs claim that the
first, second *and* last page needs to be checked.

Therefore we make it possible to set NAND_BBM_FIRSTPAGE,
NAND_BBM_SECONDPAGE and NAND_BBM_LASTPAGE independently in any
combination.

To simplify the code, the logic to evaluate the flags is moved to a
a new function nand_bbm_get_next_page().

Signed-off-by: Frieder Schrempf <frieder.schrempf@kontron.de>
Reviewed-by: Boris Brezillon <bbrezillon@kernel.org>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>