[MTD] [NAND] davinci: drop usage of cpu_is_* macro

Usage of davinci-specific cpu_is macros is not allowed in drivers.
These options should be passed in through platform_data.

Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>