[MTD] [NAND] pxa3xx_nand: moved nand definitions into shared platform header

This patch moves the exported datastructures from the pxa3xx_nand.c driver
into the <mach/pxa3xx_nand.h> header. This is a plain movement without
any modification of the attributes.

This is the first one of a set of patches which:

 * allows to specify used NAND flash in the platform code and allows to turn
   off the old way to specify NAND characteristics in the driver.  This way did
   not worked well as these characteristics depend on the platform and can not be
   derived from NAND id alone.

   E.g.  some NAND chips share the same ID (e.g.  K9K8G08U0A and K9NBG08U5A) but
   have different timings (which are written in the common driver currently and
   must be modified there).

 * adds 'const' annotations at various places

Further patches will be sent to the mtd-list.

Signed-off-by: Enrico Scholz <enrico.scholz@sigma-chemnitz.de>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>