nand: remove dead code and suspend/resume

Get rid of the several "#if 0" sections that were keeping around Linux
code that isn't relevant to U-Boot.  Besides cluttering the code, these
sections make tracking upstream changes harder, rather than easier.
It's easy to discard obviously irrelevant diff hunks that patch rejects,
but it's not as easy to notice hunks that apply cleanly to the #if 0
section, but *are* relevant to U-Boot and require modification elsewhere.

Also remove suspend/resume, as this is not applicable to U-Boot.  Removal
saves 232 bytes on powerpc.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Tested-by: Ben Gardiner <bengardiner@nanometrics.ca>