The existing NAND infrastructure allows the default main and
mirror bad block tables to be overridden in nand_default_bbt().
However, the davinci_nand driver does not support this.  So,
add fields to the davinci driver's platform data so platform
code can pass in their own bbt's and make the driver honor
those overrides.
Signed-off-by: Mark A. Greer <mgreer@mvista.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>